The series has nine posts and opens with One Month, Four Games and One Engine, which carries the map of the other eight. Nothing that went into Castle Arena is a release yet: it all ships together, after the rebalance.

— The team

This series opened with one month, four games and one engine. This post closes the account, with numbers you can check and with the pending items named.

The month in numbers

Commits between October 2 and 25, by repository:

• Castle Arena: 149, from October 2.
• Castle Survivors: 188, from October 6.
• Custom Hero Survival: 95, from October 10.
• Line Tower: 33, from October 9.
• Kastle: 116, from October 9.

About 580 in all. What they hold:

• Castle Arena: 14 factions, 15 arenas, 7 languages, a map editor, 48 options in the mode builder.
• Castle Survivors: 90 weapons and 3 extras, 97 upgrades, 36 enemies, 9 bosses, 17 worlds, 28 tower challenges, 29 achievements, 5 languages.
• Custom Hero Survival: 122 of 122 abilities, 11 shops, 1,085 tests in 49 files.
• Line Tower: the whole 12.1b ruleset, up to 12 builders, 4 nebula skies and deep space.
• Kastle: 164 creatures with 705 skins, 235 effects, 1,115 scenery models, 22 worlds, 74 sounds, 948 tests, 4 languages.

What is pending, by name

• Castle Arena. The new economy, AI and field are in the code, but the faction rebalance on top of them and the Training lessons that lost their pace are not yet. It all ships together, in one release. After that, the Steam page.
• Castle Survivors. It is at test-build state. What is left is what only testers show.
• Line Tower. Names, art, sounds and texts are provisional; its own universe is the next step.
• Custom Hero Survival. Three of the eleven soak scenarios with boosted bots do not finish the match, and MODERN keeps growing over CLASSIC.
• Kastle. The games still use their own orders and abilities; adopting the engine's is what lets each one retire its scripts. The simulation in a worker waits until a real game measures its step at peak. The Studio still picks a game's mods folder only through an environment variable.
• Infrastructure. The repositories are private and CI minutes are counted, so the performance gate runs on the machine, not in the cloud, and every CI run is weighed before it is spent.

How we worked this month

The pace came from working on several fronts at once, each with its definition of done written before it started, and from measuring before changing: AI-versus-AI matches by the thousand, determinism tests that run the same match twice, a lint that refuses what would make two computers disagree. When something broke in CI, the cause was followed to the end, even when the culprit was a GPU watchdog on a server with no GPU.

What comes next

The order for Castle Arena has not changed since post 13: recalibrate the factions, redo the lessons, run the full battery in the lab and release everything at once. For the other three, test builds in the hands of people who play. And this diary returns to its normal rhythm, one post per subject, now with four games to draw subjects from.

Thank you for reading this far.

— The team

With one game, the numbers live in the code and that is fine. With four, each with hundreds of units, abilities and weapons, touching a value becomes a hunt: which file, who uses it, what changes in the game, and the same mistake waits in every game. Kastle Studio was born on October 24 to be the one place for that: the showcase of everything the engine ships and the bench where the games' numbers are seen, tuned and measured. It runs in a window of its own, speaks English and Portuguese, and nothing done in it writes into the code without an explicit button.

The tabs

Personagens shows every creature in the library, by pack and group, with a portrait, the model at real size beside a soldier-height ruler, and every animation clip in the file, tagged with what the engine plays it for. A treadmill slides the floor at world speed while the walk clip plays: sliding feet mean a wrong stride. Height, stride, lift and tint are tuned live, and the Golpe tab marks on every attack clip the instant the blade lands, with an automatic measure that reads the end of the fastest joint's strike. Arena is the engine's real stage: island themes, weather, the hour, units standing, parading or skirmishing, shots in any look, and the renderer's numbers. It has a layout editor, with units, towers and props placed by hand. Efeitos puts each of the 235 effects on a stage of its own, once or on a loop from a quarter to twice the speed, with parameters tuned live and the cost of each in particles, draw calls and frame time. Ambiente shows the 1,115 scenery models and a demo map per pack family. Combate is Warcraft III's attack-by-armour table and the hero sheet. Áudio and Configurações close the list.

The games' tabs

Each game has its tab: Castle Survivors was first, then Castle Arena, Line Tower and Custom Hero Survival. The game exports a pack with its data, and the Studio shows units in 3D, the game's icons, factions side by side, DPS by armour type and a time-to-kill matrix of every fighter against every other. On October 25 that stopped being read-only: a record has an Editar box, with names, texts, numbers and the 3D model picked from a grid of portraits, and Salvar no jogo writes the changes back into the game's source code, in the right place, and exports the pack again. A game can also declare its pack in a single file, saying where each section comes from and what may be edited, and then needs no exporter or importer. A field can be derived, read-only, or shown in the game's unit (seconds instead of ticks).

Measure before changing

The Mudanças tab compares today's pack with the previous export's, or with a file: what came in, what left, every value before and after. And Consequências answers the question that matters: what the change does to the matches. The numbers before and after run through simulators inside the Studio (in Castle Arena, every faction against the others and every troop in a duel, ten seeds; in Line Tower, a tower against a wave of creeps), and the matchups the change touched appear ordered by how far they moved. The same engine becomes a balance gate on the command line: every matchup with fixed seeds, in about 25 seconds, failing if one moved more than 10 points.

Linked to the game

The Studio talks to a game running in development. What is tuned in Personagens can be sent to the game at once, automatically if you like, and an effect can be played in the game, on the player's selection. The other way, the game reports its screen: the scene, the frame rate, the match's clock and what the player has selected, and the Studio opens the matching record. The Replays tab opens a replay or a desync report and shows the timeline of turns, each one's commands and, with two reports of the same match, the divergence checked check by check.

And the rest

Undo and redo over every edit, search over everything with Ctrl+K, missile looks as data files a mod can bring, arena layouts publishable as mods, a visual regression that draws the Studio's scenes at fixed moments and compares them with reference images, and a doctor that checks the machine of whoever just cloned. For the team, the Studio is where every game's data comes to live. For the game, nothing changes until someone presses Save.

— The team

A house engine is an expensive decision, and we took it for a simple reason: three games in one week, each needing the same 3D world, the same creatures, the same sound, the same HUD, the same Steam, the same saves and the same deterministic multiplayer. Kastle is all of that, extracted from Castle Survivors on October 9, and no game rule. A game is a folder next to it, with its own simulation, content and words. The engine never imports a game, and an automatic check fails if one day it does.

What the engine holds

The shell: title, menus, options, credits, the room with seats, colours, teams and chat, a match's life, replays and the frame loop. The network: rooms through Steam, LAN or offline, and deterministic lockstep with checksums, catch-up, rejoin and host migration. The simulation: a fixed-step loop, a seeded random, a spatial hash, navigation with flow fields and A*, and the Warcraft III runtime, with the damage table by attack and armour type, buffs, attacks and missiles. The renderer: sky, weather, day and night, island terrain, scenery, fauna, post-processing, creatures, shots and every effect. The audio, the interface with its four HUD layouts, saves with schema migrations, Steam, mods and the Workshop. And the asset library: 164 creature models with 705 skins, 1,115 scenery models in nine packs, 17 island themes, 4 nebula skies and deep space, 235 effects and 74 sounds. The packs the games bought moved into this library, and each game ships only the folders it loads.

The first two weeks

Kastle was born with replays and desync reports, GPU creature animation, an effects atlas for towers, positional weapon sounds, and controller and Steam Deck support. The next day it became a package of its own, with tests, tools, compressed textures, content mods, an example game called Kastle Skirmish and Portuguese. It gained a Warcraft III map importer that reads encrypted entries, and the game's hero rules.

On October 24 versions 0.2.0 and 0.3.0 came out, and with them continuous integration: types, the engine-game boundary, tests with coverage floors, lint, the example played inside Electron, an audit and releases. The room and the lockstep were hardened against hostile peers, with a secret key per seat, the window's security is now enforced by the engine, and the checksum covers the whole world. The renderer gained a single table of quality tiers, scenery culling per ground cell, particles that fly on the GPU, creature detail by screen size and the fog of war overlay. The simulation gained crowd separation, fog and triggers. An offline match can be saved and resumed, a rejoining player starts from a checkpoint instead of replaying the whole match, and observers watch a lobby or a running match. Large files now go through Git LFS.

And the effects, which are what you see: sword slashes, a volley of 19 magic missiles, an RPG's school of fire, 18 glowing missiles, 16 MOBA hero ultimates, ki auras in eight levels up to dragons of light, 15 cartoon projectiles, and a new atlas with flipbooks. All procedural, and the blow of every attack clip lands the instant the blade touches.

The October 25 round

The last round was the biggest, on seven fronts at once. The Warcraft III runtime gained orders (stop, hold, move, attack, attack-move, patrol, follow, shift-queued), abilities as data (approach, cast point, mana and cooldown paid there, backswing or channel, interrupts) and a six-slot inventory, allocating no memory during the step. Navigation learned unit sizes, congestion costs and a steering that joins the flow with separation.

In the lockstep, a dropped player's commands survive the rejoin, and the checksum is split into named parts: a desync report says which system diverged, and the Studio's Replays tab marks the first one. A determinism lint flags, in the simulation's code, everything that makes two computers disagree: an unseeded random, the wall clock, a sort without a comparator, order-dependent iteration. A soak runs whole matches over simulated networks, with latency, loss, reordering and partitions, and it already found a real bug: a guest whose countdown started after the host's lost the first turns. A performance gate measures the example and a 500-body crowd against a baseline, locally, because CI minutes cost. A simulation inside a worker was measured: it saves 0.1 to 0.2 ms per frame at 5,000 units, and no game has adopted it yet. Colour-blind team palettes keep every pair of colours a minimum distance apart, in normal and in simulated vision. And the engine's screens speak Spanish and Simplified Chinese, besides English and Portuguese.

Closing the day, CI went green again on servers without a GPU: a software renderer draws the lowest tier, and the visual regression's reference images are now the server's own.

Who uses what

Line Tower and Custom Hero Survival run entirely on Kastle and have adopted the new round. Castle Survivors uses only the renderer, by decision: its simulation, network, interface, saves and replays stay its own. Castle Arena has its own lockstep and does not use the engine, but talks to Kastle Studio like the other three. The engine has 948 tests of its own today, which every game runs alongside its own.

— The team

In Custom Hero Survival you do not pick a ready-made hero. You pick a body, buy abilities with lumber in eleven shops, raise each one to level 20 and build the hero you want, while surviving level after level of creeps in your arena. Between levels there is a 30-second break to shop, and at the end, PvP rounds with bets, a Battle Royal and Elimination. The reference is the map Custom Hero Survival Z2.6 M9.8.17, and the game's first phase, CLASSIC, is the map as it is, with its rules, numbers and quirks, before any modernisation.

A ledger

The method here is stricter than in the other games. Reproducible extractors read the map and produce tables with evidence: every rule points at the script line it came from. The fidelity ledger is the reconstruction's source of truth, line by line, revised against the code at every stage, and a content matrix generated from the code says what is covered. A parity report separates, bluntly, what is 1:1, what is equivalent and what still diverges.

Fifteen days

On October 10, the first day, came the playable vertical slice: three representative heroes, the full custom ability system, the ability and item shops, level and experience, gold and lumber, the first wave, the break, the second wave, and death without respawn, as in the map (the Ankh reincarnates once). The same day, PvP rounds and bets, the Battle Royal, Elimination and item crafting. Then the ability bases in series: the actives (area spells, channels, summons), the passives, the auras, the attack modifiers and the buffs; every hero's specials across the roster; the item abilities; and the map's chat commands, from -ms to -kick, with vote-kick and periodic hints. For that the engine gained what it lacked: casting time, corpses, per-unit attack cooldown, percentage damage, damage types and illusions. The learn system was ported from the map's pickup triggers, with Random Ability, and the companions, the Faerie Dragon and the Wisps, come back, follow and heal. By the end of the first week: 120 of the 122 abilities and 763 tests.

On October 24, an ability audit and an item audit closed what was left: crafted items work, dummy kills pay income, and the last bases came in, Phoenix Fire, the invulnerability potion, the orbs, Slow Poison, Feedback, Spell Shield, Glyph of War, dispel and bouncing attacks. 122 of 122. Whole matches with bots in eleven scenarios run twice with the same seed to prove determinism (one revealed an endless rebirth loop in a lethal duel, since fixed), and the network checksum now covers the learn state, inventories, ability levels and the shops' stock. Today there are 1,085 tests.

What the map did not have

With CLASSIC standing, MODERN began: a ruleset chosen in the lobby. The shop was redesigned after a UX, controller and lockstep review: three styles (panel, merchant, anywhere), buy five at once, repeat the last purchase, and builds with quick buy after Dota 2 and LoL. The hero pick screen is Dota's "choose your hero" over the map's pick board. Heroes have a team ring, a faint halo and their name; in the Dota layout the inventory sits in the command card.

The visuals followed: icons from the bought packs for every ability, item and hero and for the HUD, an effect and a sound per ability, sword slashes on melee hits, the engine's ki auras and ultimates on the big spells, units facing where they shoot, and hero bodies in the art's own skins. Behind the menus there is a tavern, every hero inside, filmed in nine shots.

And the infrastructure: continuous integration, a Windows installer and portable build, rejoin from a checkpoint of the world, a script that opens a LAN game with a person, and the game's data going to and from Kastle Studio, hero bodies included.

— The team

Line Tower Wars is one of the most played Warcraft III maps, and the rule is simple to state: every builder holds a lane, mazes it with towers so the creeps take longer to cross, and sends creeps into the next builder's lane. Every send raises your income for good. Whoever lets creeps through loses lives. Up to twelve builders, online through Steam or against computer players.

Reading a protected map

The reference is Line Tower Wars: Reforged 12.1b. The map's script is 34,580 lines long and protected: scrambled names, regions and units created in code, texts hidden inside ability tooltips. The work of October 9 was to rebuild that string table, annotate the script line by line and cross it with the object data, separating what the map sets from the game's stock values. Where the code contradicts its own tooltip, Line Tower follows the tooltip. The content is generated straight from the map's data, and a document says, line by line, what matches and what does not yet.

From the map came the lanes and the maze, the builder, the shops and their stock, the sends, the income, lives and recycling, research and Start Tech, every tower and creep trait, the Technology Discs, the modifiers, the computer players, rating and skins. The map is treated as untrusted data: copied into an empty folder and read by extractors that never execute anything from it.

The day the engine was born

Line Tower was the third game to start in a week, and the first not to start from scratch. The core of Castle Survivors, everything that was not one of its rules, moved to a package of its own the same day: Kastle. Line Tower is "the engine plus a game folder", with its manifest, simulation, content, lockstep session and screens. The engine never imports the game, and an automatic check guarantees it. What Kastle is, and what it became over the next two weeks, is in its own post.

What already plays

In a few days Line Tower gained what a game needs to be played: replays and desync reports, a deep space map with lane thumbnails for every map, four maps with nebula skies, a random map, and sheep running the gauntlet behind the menus. A quick tutorial of eight guided steps in a sandbox. Shots per weapon, creep factions and soundscapes per map. The hologram build ghost, range rings and a grid drawn by shader, the builder striking with a pickaxe while a tower goes up, cannons with ballistic aim and barrels that aim by distance, effects for building, upgrading and selling, and what each button undoes. Weapon recipes with element variants and positional sound, art on the command card and the utility buttons, and creature animation on the GPU.

The network was tested deep: an end-to-end test with two LAN instances that drops and reconnects a player, and harder soak scenarios. The game has a Linux build for Steam and the Steam Deck, with a Deck guide, and plays entirely on a controller: the D-pad walks the summoning circles, Y researches, View goes home.

On the 24th and 25th Line Tower exported its data to Kastle Studio, started taking back what is edited there, adopted the engine's new round (a rejoin that carries in-flight commands, checksums by part, the determinism lint), and gained the one-command Steam test build.

What is still provisional

Line Tower's names, art, sounds and texts are our own, but provisional. The game's own universe is the next step.

— The team

The previous post left Castle Survivors with an island, ninety weapons and bosses. This is the story of the ten days that followed, in which it became a game you can hand to testers.

Seventeen worlds

The island got themes, and then siblings. First the islands in the sea: Spring Isles, Autumn Hollow, Frostward Isle, Coral Atoll, Ember Peak and Mirewood. Then five lands that are not islands: Cascade Valley, walled by cliffs, with waterfalls and a river with bridges; Bamboo Grove, with moon gates and a stream; Sky Peaks, a plateau over a sea of clouds; Terraced Hills, with wheat terraces and farmhouses; and Moonlit Garden, walled, with a canal round the castle and lanterns. Finally Sakura Sanctuary, by day and by night, Lantern Festival, Stilt Village, Ruined Temple and Rose Garden. Each world has its own colour grading and bloom, and particles in the air: petals, leaves, fog banks, sun shafts, waterfall spray. The lanes, the castle and the simulation are the same everywhere; only the look changes. Maps are challenge rewards: each themed challenge skin unlocks a world, and the map cards show the island drawn.

Faithful to 1.91 to the end

A full fidelity pass closed what was left of the original map: mana shield, night lighting, the upgrade pools, the Philosopher's Stone, the kill bounty fields, Transmute, burn, the degeneration Ankh, Set Seed and the Daily Seed. The scoreboard shows 1.91's values, there is a DPS meter, a build summary, personal damage and income records, and damage-type marks. The host picks the match speed: 1×, 1.5× or 2×. AI rivals come in Easy, Normal and Human, and the Black Market joined the command card as a secret shop.

How it plays, and how you learn it

The HUD gained four layouts: Default, TFT, Imp and Dota, and the tower picker was redesigned, with castle snapshots on the skin cards. There is an endless solo mode, Beyond Samwise, and mythic endings for the Clear, the castle's fall and victory. First Battle is a guided three-minute tutorial, with smart hints over the shop after it. Builds can be saved and shared by code. Every key is rebindable, with Warcraft III's grid style for the command card, and there are pings with a radial wheel, markers in the world and on the minimap and edge arrows.

In multiplayer, Quick Match fills rooms that start on their own, and the lobby came alive: vote-kick, a bot takes over whoever goes AFK, invite in one click. There is a war room, standings on the HUD and the option to watch rivals on their own map. Crashes and errors are logged, with an error panel in the game and a bug report (F8) that produces a file to send.

For more people

Accessibility: colour-blind palettes, including the lobby's player colours, flash intensity and fewer particles. Languages: the whole interface was extracted into dictionaries and translated to Brazilian Portuguese, then to Japanese, Simplified Chinese and Korean. The Steam Workshop takes mods: data-only gameplay mods and cosmetic mods, with a Modded leaderboards tab and the choice to keep or remove a room's mods. Achievements and unlocks were checked as reachable under 1.91's rules, and every map can be unlocked.

The road to Steam

The game's icon comes from its own crest, embedded in the executable. Every art, music and sound pack shipped has its licence noted and its credit on the credits screen, and 49 MiB of unused material left the package. One command, steam:build, makes a Steam test build of any commit. The Steam docs describe the release state.

A hardened network, and the engine on screen

On the 24th and 25th came a security round: the window under a strict content policy with permissions refused by default, a seat proven by a secret key rather than the install id, oversized envelopes refused before they leave, the room chat bounded, and saves written durably and in order, never overwriting a profile this build cannot read. And Castle Survivors started drawing with Kastle: the engine that came out of it returned as a submodule, for the render layer only (the missile looks and the MOBA ultimates came along). The simulation, the network, the interface, the saves and the replays stay its own. The game's data goes to Kastle Studio and the edits made there come back into the game.

— The team

Castle Survivors is a survival and tower-defence game of one kind: a castle in the middle of an island, armies wading out of the sea from every side, and no troops of your own. The castle fires every weapon you buy on its own. Your part is the shop: every 30-second round you choose what to buy, and the choices stack until the castle becomes an absurd war machine. The rules are those of Tower Survivors 1.91, the Warcraft III map: 30-second rounds, +5 income per round, a restocked shop each round, a 100 + 100 reroll, the Clear and the final boss at 60:00, doubled armour affinity, and top-four placement.

The first day

On October 6 the game went from nothing to running. The foundation is the same Castle Arena uses: a headless simulation, 30 steps per second, with a seeded random, giving the same result on any computer. The tests check that. On top of it, still on the first day, came the island arena with a fixed camera and enemies arriving from 360 degrees, a HUD in the style of classic RTS games, a dev panel, 30 weapons, a Windows package, the menus, and the tower and specialisation pick before a run with a 30-second preparation. And multiplayer: Steam lobbies, direct connections between players and AI rivals when you play alone.

The island

The island is real terrain: a coastline, relief, a pond, islets, and a sea that knows its depth. Units follow the ground, raise wakes when they wade in, and ground effects drape over the relief. The scenery was laid out again on the new terrain: groves, landmarks, the coast and a fishing cove, with fewer trees so the battlefield stays open. The sky became a dome with sun, moon, stars, clouds and weather, with rare events, and the camera can tilt to the horizon so you can see it. There is day and night, night lights and wildlife.

The castle grows with you. It is assembled from the pieces of a medieval hexagon pack: it grows with the level, gains a piece per weapon bought and shows its damage. The castle got bigger, with walls, towers and gates to fill the plaza from level 1.

Ninety weapons, one by one

Weapons and upgrades were checked one by one against the map's reference database: today there are 90 weapons (plus 3 unlockable), 97 upgrades, 36 enemies, 9 bosses, 15 attack packs, 28 tower challenges, 11 unlock challenges and 29 achievements. Every ability in the database has a visual effect of its own, every weapon a signature, and hits use stylised effects ported from a pack. The 1.91 spawn system was ported line by line, enemies use the map's Object Editor values, the economy is 1:1, and armour and attack types and random targeting follow the original. Enemies change their looks by era, drawn from three creature packs.

The Codex shows all of it: every weapon has a looping animated preview, which is a real miniature simulation drawn from above, enemies and bosses have portraits and a live 3D viewer, and the extra weapons show as locked or unlocked.

Bosses, and the game around the game

Bosses are mechanical: each has one to three mechanics, with a telegraph before the big hits (a stun interrupts it) and a stagger under burst damage. Around them came the meta's foundations: challenges, unlocks, cosmetics, the Daily Siege, leaderboards, and co-op, where several castellans' islands are linked over the same match protocol, with an island overview and spectators. In co-op the horde grows gently: 10% more pressure and boss HP per extra castellan. Stacked bonuses have diminishing returns, so the late game does not snowball.

All of that in two days, October 6 and 7. What came next, the seventeen worlds and the road to Steam, is in the next post.

— The team

Post 13 ended on a promise: a new economy, a new AI, a larger field, all held back to ship together. Between October 8 and 13 that foundation landed in the main code, and more came with it than fits in one post. None of it is a release yet: the game is still 0.1.0 and has entered a refinement period, where preserving what exists counts for more than rebuilding.

A map editor

Until now every arena was drawn by hand, in code. Now there is a map editor: the 2D plan and the 3D scenery in the same window, Tab switching between them without reloading anything. In 3D, linked symmetry (the M key toggles it), ground painting, lines of models, sets and favourites, align and distribute, lock and hide, stamps and a draggable time of day. On the plan, multi-select, copy and paste, a reference image, a ruler, route heat and a side-by-side comparison of the two halves. A command palette with configurable shortcuts, shared undo, an unsaved warning and recent maps. On publish, the editor refuses models the game cannot mount, and a button tests the map in the game itself. It ships packaged for Windows.

Moss River, the 15th arena

The first arena made entirely in the editor. The bases sit atop two plateaus, and the battle runs down the ramps into a valley of dense forest cut by a river with two bridges. What the editor produces enters the game as data: loose models at the pack's scale, sculpted relief, ground paint and a clean area where the automatic scenery does not grow. The Steam stat and achievement for arenas went to 15. The plan for the Harbour, the next one, has begun.

New faces, again

Post 12 brought models for four races. Now the undead, orc, dwarf and barbarian kits of the Toon RTS pack came in, with new cavalry and infantry for elves and humans. The Bone Legion swapped its old skeletons for the undead, and every faction picks the colour of its clothes from the pack's texture, so two factions never repeat the same model in the same colour. Twenty-two troops became real creatures: bears, wolves, a tiger, boars, a crocodile, a turtle, a crab, eagles and a bat from one pack, dragons, a bull, a gargoyle and goblins from another. Creatures sleep, get stunned and howl. The Ancestral Beast, the Giantess and the Gear's machines got bodies, and so did the Hex's sheep. Buildings and scenery from the Toon RTS and Fantasy Village packs, buildings in the faction's colour, mesh weapon effects, water with a bed, caustics and ripples borrowed from Castle Survivors' pond, and the Rescue with the look of its Clear.

Icons went the same way: a 500-icon pack for the shop, build buttons by troop type, no icon repeated within a faction, and the slots of the card, the inventory and the shop filled in.

The Arena HUD

Options › Interface has a new HUD style, Arena, after Dota 2 and TFT. It is a skin over the same interface: the scoreboard pinned to the top with living troops in a big number, the build card as a 6×2 card shop with its border by cost tier, and gold with the income pips. The battle setup screen shows the whole arena, with panels in drawers and a summary strip with Start. The bestiary, the war room and Create mode follow the same model. Also in: Alt+Enter for fullscreen, big text and controller at 1280×720, the build card showing the troop in 3D, perk cards with icons, each map's plan on the arena pick, the castle gates as a loading screen, allies in a dimmed tone in team matches, tips in the online room and the window opening at the monitor's size. In the Default style nothing changes.

The rules, read from the script

The invisible part is the biggest. The Castle Fight DE economy that post 13 described is in for good: 250 gold and 125 lumber, a base income of 5 every 7 seconds, a 5,000 castle, a bonus for the first build, buildings and upgrades at DE's times and income that dies with the building. The AI upgrades early. Damage became base plus die. Then we read the EU 2.0.42 map's script function by function, 32 for troops and 34 for buildings, and DE 9.33's object data confirmed 91 of the 105 numbers: splash that hits the main target, preferred targets, mines with an arming time, spells drawn from a group, buildings born without mana that only cast after a full cadence. The Archon draws one of two spells, the Obelisk heals the wounded first, Ruin has ten outcomes, the Fist of Hell never lands on the castle. About 30 values that were estimates were resolved, and every number now carries the mark of where it came from. The AI's spawn tuning was recalibrated: from 20.3 to 2.6 points of deviation over nearly three thousand matches.

Two doubts only a running DE could settle were checked in DE: Rot at 20 per second and Roots at 4 and 5 seconds were already right in the game. The orb's Phoenix Fire stays unmodelled for now.

And the Studio

On the 24th and 25th Castle Arena started exporting its data to Kastle Studio and taking back what is edited there, straight into its code. That subject has a post of its own.

— The team

The last post in this diary went out on October 8, and since then the workshop has not stopped: it changed size. Castle Arena is still the game that gives this site its name, but today it shares the bench with three other games and with an engine that serves all four. This series of posts is the diary of that whole month, October 2 to 25, told game by game.

The four games

All of them come from the same source: the Warcraft III custom maps we played for years. Each is a faithful reconstruction of one of those maps, with the original's rules and numbers, made as a game of its own for Steam, with no Blizzard material in it.

• Castle Arena (since October 2). Castle Fight's tug of war: you build, the buildings train troops on their own, the troops march. Everything this devlog told up to post 14, plus what came after.
• Castle Survivors (since October 6). A castle on an island, armies wading out of the sea from every side, and a castle that fires every weapon you buy by itself. The reconstruction of Tower Survivors 1.91.
• Line Tower (since October 9). Line Tower Wars: every builder holds a lane, mazes it with towers and sends creeps into the neighbour's lane. Up to twelve players.
• Custom Hero Survival (since October 10). You build your own hero by buying abilities and survive level after level of creeps. The reconstruction of Custom Hero Survival Z2.6.

And the engine

The first three games each started from scratch, and within days it was clear we were writing the same thing three times: the 3D world and its effects, the creatures, the sound, the HUD and menus, Steam, saves and lockstep multiplayer. On October 9 that core left Castle Survivors and became Kastle, the house engine. Line Tower was the first game built on it, Custom Hero Survival came the next day, and Castle Survivors now draws with it. Castle Arena keeps its own code, but already talks to the tool that comes with the engine, Kastle Studio, where the numbers of every game can be seen and tuned in one place.

The map of the series

1. Castle Arena: a map editor, the 15th arena and the Arena HUD
2. Castle Survivors: a castle, an island and ninety weapons
3. Castle Survivors: seventeen worlds, co-op and the road to Steam
4. Line Tower: the maze that gave birth to the engine
5. Custom Hero Survival: 122 abilities, a ledger and a tavern
6. Kastle: the engine the four games share
7. Kastle Studio: the bench where the numbers live
8. Where we are: the month in numbers and what comes next

For now the diary of the four games lives here, on Castle Arena's site. If it ever gets a home of its own, we will say so right here.

— The team

Castle Arena's first fog of war was made of clouds. They covered the map and parted for good wherever your troops went. It looked nice, but it did not help you play: once you explored an area, it stayed open forever and told you nothing about what was happening there now.

Three states, like the classics

We swapped the clouds for a dark veil, the way Age of Empires, Warcraft and Dota do it:

• Never seen: nearly black. You don't know what is there.
• Explored: dimmed. You see the terrain and remember the buildings you saw, but not the troops moving through.
• In sight: clear. This is the only place enemy troops show up.

Sight reveals the map

Each of your troops, buildings and your castle has a sight radius, and those radii are now large: 12 cells for a regular troop, up to 15 for ranged ones and 15 for the castle. Sight is updated all the time. As your troops push forward, the veil opens ahead of them. When they die, the area falls back into the dim. The minimap follows the same rule.

Fog stays visual only. The simulation and the AI know nothing about it, so online matches run the same on both computers, and each player sees the map through their own army.

— Castle Arena Team

The last two days went into foundations. Little of it shows in a screenshot, but all of it changes how a match plays. And none of it has reached a release yet: it is held back to ship at once, after the balance is redone on top of the new rules.

An economy that was too rich

We measured the pace of our matches against what we expect from a game of this genre. Troop production was right. The money was not: the game ran 3.5 to 4 times richer than it should, and every match turned into a flood. So we tightened the economy:

• Quick construction: 2 seconds for troop buildings, upgrades and specials, and 20 for towers.
• A tighter start: 250 gold, 125 lumber and 5 income from the castle, instead of 300 and 14.
• Income dies with the building. A destroyed building used to keep paying. Now losing your base really hurts.
• A reward for building first: the first four players to finish a building get 20, 15, 10 and 5 gold.

Some of these values are still provisional and flagged for review after testing.

An AI that upgrades on time

We reviewed the 66 relations in our upgrade tree one by one, and the tree held up. The problem was the AI, which upgraded too late and at random. Experienced players take the first upgrade as soon as they can, and that is what the AI learned. With that policy, the new AI beats the old one in 77 to 78% of matches.

Hits that vary

Each hit now deals a base damage plus a variation, instead of a fixed value. Reviewing the tables, we found about 150 troops whose minimum damage sat one point below what we intended. On some, like one of the water elementals, the weakest hit came out at almost half strength. We fixed the damage of every faction and reviewed 35 ability numbers that were still estimates.

A field three times larger

The playable field went from 96 × 27 to 160 × 47, nearly three times the area, and all 14 arenas were redrawn from scratch under the same names.

The inspiration is the classic strategy map: paved roads, dense groves, lakes, fords, terraces and landmarks in the background, such as temples, mossy monoliths and floating crystals. The relief is visual only. Troops still move on a flat plane, but everything drawn follows the ground. And one new rule: no troop walks through a piece of scenery. If it looks solid, it is solid.

What is left

Each of these changes, on its own, throws the factions off balance. Tuning them one at a time would mean redoing the work at every step. So the order is: finish rebalancing the factions with the new economy, AI and field, run the full battery of lab matches, rework the Training lessons that lost their timing, and only then ship it all together.

— The Castle Arena Team

• New 3D models for the Crown, the Gear Guild, the Horde riders, the three elf factions and the spiders, and new buildings for humans, elves, orcs and the undead. Buildings now smoke and burn as they take damage.
• Music and sound: new menu and battle tracks that rotate with a smooth crossfade, weapon and spell sounds, forest and sea ambience, death voices, and a spoken herald.
• A faster march: troops and workers walk 1.5x faster, without touching the fights, so every faction keeps its balance.
• Single-player matches can be saved and continued later.

The full list is in the release notes.

— The Castle Arena team

For a while the armies looked like the first draft they were: models borrowed from a single style, and a battlefield that was almost silent. These two days went into fixing that, without touching the rules.

Faces

Each model is now a mesh plus a style. The three elf factions share one set of models and tell themselves apart by costume: the Sun Court, the Moon Sentinels and the Ancient Grove (with its bear shamans and bear riders). The Crown, the League of Gears and the three Horde riders got new models, and the spiders now come from one single mesh in four skins, so the Black, the Giant, the Brood Matriarch and the Forest spider are family.

Making a new model walk, fight and die is half the work. Each pack ships its own clips, so every model uses the ones it brings: a creature without a spawn animation simply starts walking instead of freezing for a moment.

Walls

Humans, elves, orcs and the undead now have their own 3D buildings, and a building's level follows the evolution chain: the first tier looks humble, the last looks proud. Factions of the same race share the shapes and change the tint: the Crown and the League of Gears, the Sun Court, the Moon Sentinels and the Ancient Grove, the Bone Legion and the Corrupted.

Buildings also show the damage. Below 60% health they smoke, below 30% they burn, and the castle falls in flames. It is a small thing, but it lets you read a siege without looking at a single health bar.

Sound

The game now has a soundtrack: one track for the menu and several for battle, which rotate with a smooth crossfade (there is a setting if you'd rather keep one). On the battlefield, swords, bows and spells have their own sounds, gates and doors creak, mining clinks, and forests and seas have their ambience. Humans and monsters die with a voice, and the herald, the one who warns that the castle is under attack, now speaks. The subtitles still match what is said.

Faster march

Walking across the arena took too long. We tried speeding up the whole clock, and it worked, but it also changed how the fights felt and moved the balance numbers we had already adjusted. So we undid it and sped up only the walk: troops and workers move 1.5x faster, while attacks, spawns and the clock stay as they were. The wait between waves shrinks, and the balance stays where it was.

A trail for desyncs

On the online side, when a match goes out of sync, both players now get a saved replay of it, even with "Save replays" off. Two replays, one from each side, show whether the orders differ or where the simulation drifted apart. It is the way we'll find the few cases still left.

— The Castle Arena team

How it works

• Every tie you play is a real match, best of 1 or best of 3, with the AI level and arena you choose.
• The ties you are not in are played out by the AIs on the spot: you never wait.
• If you go out, watch the next tie live or simulate the rest of the tournament.
• The tournament is saved: close the game and carry on later, right where you stopped.

A loading card also arrived: when a battle starts, the screen shows the arena, a line from one of your faction's troops and a tip. The full list is in the release notes.

— The Castle Arena team

Team battles are now truly online. Every seat can hold a person: from 2v2 to 4v4, up to eight players in a Steam room, plus four spectators.

What changes

• In the room, each team is a column of seats. Pick yours with Sit here; empty seats go to the AI.
• 4v4 also arrives in matches against the AI and in AI vs AI.
• If someone drops, the AI takes their seat right away, and the player gets it back on return, without the match stopping for anyone.
• Surrender is now a team vote: the team gives up once the majority votes.
• In draft modes, picks follow a 1-2-2-1 order across all players.

How it works under the hood, and what testing with eight windows open caught, is in the devlog: Eight People, One Battle.

— The Castle Arena team

What you will find here

• Devlog: long-form posts on how the game is being built, from the economy to online play, with the reasons behind each decision.
• Game Guide: the same reference you find under How to play in the game, expanded with practical advice.
• Library: all fourteen factions with every building, troop and ability, plus items, perks and arenas. These pages are generated from the game's own data, so they always match the version you play.

The site speaks English and Portuguese, just like the game. Use the language link at the top of any page.

The Steam store page is not open yet. When it is, the Play now button will take you straight to it.

— The Castle Arena team

In yesterday's receipt, the list of unfinished work had one line saying "online with more people". Online team matches were you and a friend, each with AI allies. Now every seat can hold a person: from 2v2 to 4v4, up to eight players in a room, plus four spectators. Empty seats still go to the AI, so you can play a 3v3 with four friends and two AIs.

The room

In the room, each team is a column of seats. Whoever joins sits in a free seat on the side with fewer people and can move with Sit here until they mark Ready. Empty seats say "AI slot". Within a team nobody repeats a faction (unless the game mode allows it), and Ready now warns you right away when your faction clashes with a teammate's, instead of letting the host find out when trying to start. The public room list shows the format and how many players are already in.

In draft modes, picks follow a 1-2-2-1 order across all players: the first player of one side, two of the other, two of the first, and so on. AI seats pick on their own when their turn comes.

A star, not a web

With two people, the two computers trade orders directly. With eight, connecting everyone to everyone would take 28 connections, each able to fail in its own way. So online team play is a star: every guest talks only to the host, and the host relays each player's orders to the others. What travels is still just orders, a few bytes per turn, and every computer runs the whole battle, just like in 1v1. The battle "fingerprint" checks go through the host too.

When someone drops

In 1v1, if the other player drops, the match pauses and waits. In a 4v4 that would be unfair to the other six, so here it works differently: the AI takes over the dropped player's seat right away, from the same turn on every computer. The switch is recorded as an ordinary order, so the replay and the spectators show exactly the same thing.

The dropped player opens the game and picks Rejoin match. The host sends a full snapshot of the battle, and the AI keeps playing for them while their computer builds the scene and catches up. Once they're in sync, they ask for their seat back and take over on an agreed turn, far enough ahead that everyone knows before reaching it. Nobody stops to wait.

And if the host is the one who drops? Then there's nobody to relay, so everyone else pauses with the reconnection countdown. When the host comes back, they ask every guest what they saw since the drop and take the snapshot from the furthest along, merging in the orders only the others had received. If the host doesn't return in time, their team loses by forfeit.

Surrender is now a vote: the team gives up once more than half of its people vote. If you're the only person on your team, you surrender right away, as before.

What eight open windows taught us

Tests without graphics simulate 2v2 to 4v4 with guests and the host dropping and returning, and check that everyone ends up in the same battle. But we also ran the real game: four windows for a 2v2 and eight for a 4v4, all on the same machine, with the AI playing for each person. Mid-match we closed one window and reopened it. Every window finished with the identical battle. Along the way, four problems showed up that the tests without graphics didn't catch:

• The room that never started. Everyone joined with the default faction, and a team can't repeat factions. That's where the warning on Ready came from.
• The guest who gave up joining. With eight windows loading at once, the host was slow to answer, and the join request went out only once. Now it keeps trying for up to 20 seconds.
• Everyone waiting on one. In the first version, the seat went back to the returning player the moment the snapshot was sent, and the other seven waited about 30 seconds for their scene to load. That's how the AI ended up holding the seat until the player catches up.
• The slowest PC at the start. Anyone who took more than 8 seconds to set up the match lost their seat to the AI before the first turn. Now a player still loading gets 45 seconds.

There was also a subtle one, found by reading the code: a guest can run a few turns ahead of the host, and if their seat came back on a turn they had already passed as AI, the match broke. That case now has a test of its own.

What's still missing

If the host drops and never returns, nobody takes over the room: their team loses. And orders always go through the host, even between two allies. Both are on the list.

— The Castle Arena team

Castle Arena now plays with teams. Each side can have two or three players, and every player controls a worker of their own.

How it works

• The side is shared: castle, territory and troops fight together.
• Everything else is personal: gold, income, perks, crystals and kill rewards belong to each player.
• By default a faction cannot repeat inside the same team, and there are options to change that.
• Empty seats are filled by the AI, so you can play 2v2 with a friend against the computer.
• Team rules keep things fair: allied Rescues share a cooldown, and at the time limit the tiebreak adds up the whole team's Rescues and income.

Team matches work online, in replays and in series, and the classic 1v1 plays exactly as before. See all the options on the Game Modes page.

— The Castle Arena team

This is one of the biggest changes to combat so far. Every building and every troop of the fourteen factions now has its full set of abilities: spells with mana and cooldowns, auras, summons, illusions, mind control, effects that trigger on hit or on death, and abilities that grow stronger with the number of buildings you own.

What changed for you

• Tooltips show every ability, each on its own card with the numbers that matter.
• A floating "miss" now appears when an attack is evaded, so you can see blinding and curses at work.
• The AI builds smarter: it weighs which troop buildings work best, builds support structures sensibly and answers flying troops in proportion.
• Online matches use the same numbers for everyone. The small compensations that help the AI apply only to AI teams.

Browse every faction and ability in the Library. The long story behind this update is in the devlog.

— The Castle Arena team

Leave the main menu alone for a few seconds and it starts telling stories. Every fourteen seconds or so the background switches to a new vignette, in shuffled order: a clash in the lanes, a siege at the base, a march to war, wings over the field, a base rising and a night watch.

Each vignette rolls its own factions, arena, time of day and weather, with a discreet caption. The battle scenes are real: a short simulation runs behind the menu, quietly, with the same rules as a match.

Better info before the battle

On the Prepare for battle screen, hovering or focusing a troop portrait now shows the same card you see in a match: the troop in 3D, its stats, abilities and matchups. Click it to open the Bestiary on that entry, and Back returns to the setup with your rolled perks intact.

— The Castle Arena team

What's new

• Mode builder: pick a base mode and stack options on top of it, or start from one of the ready-made modes.
• Drafts: factions can be picked in turns, so the matchup becomes part of the strategy.
• Series: play best-of rounds, with factions kept or re-rolled between rounds depending on the mode.
• Compendium: every command has its own card and pixel icon, and options that don't apply to the current format are shown muted.

The full list, with what each option does, is on the Game Modes page.

— The Castle Arena team

Our biggest update so far touches almost every part of the game.

Battle

• Flying troops: they cross woods, water and walls, can't be caged, and can only be hit by troops and towers that attack the air.
• Fog of war, as a match option: you only see what your side explores.
• Melee crowds now flow around each other to find a spot to fight instead of piling up behind the front line.

Online

• Reconnection: if a player drops, the match pauses with a 2:30 countdown, and Rejoin match on the main menu brings them back where they left off.
• Spectators: up to four per lobby, with a broadcast delay chosen by the host.

Everything else

• Full controller support, including the Steam Deck.
• Water reflections, grass that bends under troops, rare events like auroras and eclipses, and wildlife that runs from the fighting.
• Music that changes with each faction and arena.
• A coat of arms editor, a Bestiary with 3D previews, sound captions and six colorblind-safe team palettes.

— The Castle Arena team

Devlogs tend to be about the shiny parts. This one is a receipt. Every number below was counted from the project itself on October 3: the history of changes, the source code, the game data and the test folders. Where a count depends on how you slice it, we say so.

Three days

Castle Arena's first design report is dated October 1, 2026. The first commit (a saved, described set of changes) landed shortly after midnight on October 2, and the latest at 11:30 pm on October 3. That's three calendar days and 43 commits. Some are one-line fixes; others carry a lot of work at once.

The receipt

A few notes so the table doesn't oversell itself. The line count covers everything written in TypeScript, so faction lore and the English dictionaries count too. "Troop types" includes every unit in the faction data, such as skeletons raised from corpses and creatures summoned by spells. The translation count adds up the English entries across 74 dictionary files; a handful of them are patterns that cover many sentences at once.

What the checks do

The checks deserve a line each, because they're why we can move this fast without breaking things:

• Tests cover the rules, abilities, game modes, team matches, Training lessons and game data, and run four minutes of AI play for every faction.
• Lockstep check plays the same match on two simulated computers and proves they stay identical, which is what online play depends on.
• Replay check makes sure replays play back to exactly the same result, including jumps in time.
• Resync check drops and restores players and spectators, then compares the results.
• Translation check flags any text without an English version.
• Visual check photographs fixed scenes with a frozen clock and compares them with our 74 reference screenshots.

We also wrote 14 design reports: rules, balance, interface, Training, stalemates, crowd fighting, flying units, game modes, team matches and more. Several of them changed our minds, as you can read in Two Hard Problems.

What's next

No dates, just the honest list of what our own notes mark as unfinished:

• A Steam store page. Castle Arena doesn't have its own page on Steam yet.
• Flyers that look the part. Flying troops still use procedural wings; real 3D creatures are on the list.
• Online with more people. Online team matches are still two humans plus AI allies.
• Balance, always. Our latest AI round-robin puts every faction between 42% and 57%, and we're keeping a particular eye on the Abyssal Pact.
• Estimated numbers. Some ability values, mostly for summoned creatures, are still our own estimates and are flagged for review.
• Training. One lesson teaches its point less sharply since the melee movement changed, and a lesson about perks would be the natural next step.
• A known bug. The minimap can still show invisible enemy troops.

That's where Castle Arena stands today. We hope the next receipt is a longer one.

— The Castle Arena team

Fourteen factions is a lot for a small team, and for a while part of it was a sketch. Every building, troop, upgrade chain and legendary was in place, with its costs, HP and spawn timers, but our engine only knew 17 kinds of effect, so any exotic ability got squeezed into the nearest one. A legendary hydra that should split into smaller hydras simply came back to life once. Curses meant for a single target became weaker auras.

The fourteen

• Crown: knights, marksmen and mages, with blessings and holy resurrection.
• Bone Legion: zombies, necromancers raising skeletons, vampires that turn their victims.
• Steppe Horde: brutal infantry, shamans who empower the troops, war beasts and totems.
• Sun Court: nimble archers, critical-striking swordsmen and solar magic.
• Moon Sentinels: multi-target arrows, binding roots, assassins and specters.
• Ancient Grove: poisons, healing, stunning bears and stone giants.
• Northern Clans: swift wolves, frost spearmaidens, freezing trolls and the endless winter.
• League of Gears: tanks, flamethrowers, automatons and energy shields.
• Abyssal Tide: regenerating scaleborn, bouncing serpents and a hydra that splits.
• The Corrupted: cursed trees, armor-eating void creatures and infernal engines.
• Abyssal Pact: demons, volcanoes and spells that wipe out whole armies.
• Kingdom of Sands: quillbacks, vultures, brutes, sand mages and storms.
• Elemental Conclave: spirits of wind, water, fire, lightning and earth.
• Jade Empire: healing monks, hard-to-hurt drunken brawlers and celestial chi.

They fight on six arenas: River Valley, Autumn Crossroads, Frozen Lake, Dune Canyon, Murky Swamp and Citadel Ring. Field, castles and territories are the same size everywhere. What changes is the no-man's-land in the middle (woods, rock or water, always symmetric), the biome and, in the Citadel Ring, walled bases and a road nobody can build on. In our tests of the first five arenas, none favored a side.

Abilities as data

The fix was a new engine in which every ability is data: a trigger (on attack, when struck, on a kill, on death, whenever mana and cooldown allow, or when you press a button), its targets (the nearest enemy, the most wounded ally, the biggest group, a point in the enemy base, a line, a cone) and its effects. That let every faction get its complete ability kit: spells with mana and cooldowns, lasting curses, frozen and disabled buildings, sheep, banishment, invisibility, summons, mind control, instant death, corpses and resurrection, mines and storms on the ground.

The Bone Legion was rebuilt from the ground up: zombies in three tiers, Vampires that grow into Vampire Lords, the Wailer, the Flesh Golem, the Death Pit and the City of Decay. Two buildings even have abilities you fire yourself, the Northern Clans' Winter's Wrath and a burst from The Corrupted's Well of Torment. Everything stays deterministic, so both computers in an online match calculate exactly the same battle. Where we had no hard number, such as the stats of summoned creatures, we estimated and flagged it for review.

Teaching the AI

The first AI-versus-AI round after the update was humbling: win rates ran from 10% for the Abyssal Tide to 86% for the Jade Empire. We tested the causes one at a time. Jade without its monks' Healing Spray fell from 87% to 40%; the Horde without its shamans' blessings, from 71% to 35%. The AI was part of the problem too. It poured gold into the Abyssal Tide's weakest line, and as the League of Gears it built several Power Plants whose auras don't stack, plus far more Hangars than any anti-air need called for.

So the AI learned three things: one Power Plant is enough, anti-air should match how many flyers the enemy really has, and each troop building gets a weight from win-rate data compared with the rest of its faction. Whatever imbalance remained, we evened out by making each faction's AI train a little faster or slower. That adjustment applies only to AI teams: you always play with the faction's actual numbers, the ones in the tooltips, against the AI and online.

The final round put every faction between 43% and 56%, a spread smaller than the round's own noise. The honest caveat: that balances the AI, not players. How the Jade Empire fares against the Abyssal Tide between two humans is something no simulation has measured yet. Browse them all on the factions page.

— The Castle Arena team

The default Castle Arena match is simple: pick a faction and play one round of up to 30 minutes. But a tug-of-war battle changes a lot when you change what each side gets before it starts. So we built a full system for game modes, then made room for more players per side.

A mode is a recipe

Every mode combines a base, a series length, a time rule and options. The base decides how factions are assigned: each side picks, gets a random one, both get the same random faction (Mirror), or they draft in turns, either once for the whole series or again every round. Two bases are wilder. Ultimate gives each side one random building per slot, drawn from all 14 factions, always with at least one legendary. In Ultimate Draft, each side chooses one of two building packs five times, then one of three perks.

On top of that you can stack options: starting gold, lumber and legendary crystals, a faster or slower income cycle, a lumber cap, different income tax levels, no artillery, no legendaries, no shop, no Rescue, no syncing, faction bans, fog of war and more. Coins drops a 20-gold coin into each side's territory every 40 seconds for the worker to collect; Crazy coins drops ten at a time. Domination grants +50% income that cycle to whoever controls both lanes.

The mode builder

Edit mode opens the builder. On the left are ready-made modes such as Random best of 3, Draft with bans, Coin party, Blitz, Troops only and Until it falls, plus My modes, where you can save up to 40 of your own. In the middle, the Builder groups every option by section, each with an "i" that explains exactly what it does. The Compendium tab lists all 48 commands with search, filters and a pixel icon for each. On the right, the mode is summarized in plain sentences next to its mode string, a short code like -rr3-nt-cc that you can edit, copy and share.

Drafts and series

When a round needs choices, a draft screen opens in the war room before the battle: bans, faction picks or Ultimate Draft packs. Online, each choice has a 30-second timer, and the game picks for whoever runs out of time. During the match, a strip under the HUD shows the series score, domination and coins, and the result screen offers Next round. Draws don't count as points, and surrendering ends the series.

Some rules had to fit how Castle Arena works. Your worker never leaves your own territory, so each side gets its own coins in mirrored spots. Bans always leave at least four factions in play. And everything random in a draft comes from one seed shared by both computers, so online players only exchange their answers.

2v2 and 3v3

The newest piece is Format: 1v1, 2v2 or 3v3, in the battle setup and in the online room. In a team match every player has their own worker, gold, lumber, income, perk, crystals and Rescue. The castle, the territory and the troops on the field belong to the team. Anyone can build anywhere in the team's base, but only the owner controls a building, and a spot an ally has marked stays reserved. Using your Rescue puts a two-second cooldown on your allies' Rescues. War Drums, Marching Pipes and Fury boost the whole team but don't stack between allies. If time runs out, the team with the most Rescues left wins, with combined income as the tiebreaker.

Against the computer, your allies and the extra enemies are AIs, and each one claims its own strip of the base. Online, the two players lead opposite sides, and AIs fill the remaining seats on both computers.

Should a 3v3 castle be three times as tough? We measured it. Matches lasted 10.1 minutes in 1v1, 12.1 in 2v2 and 13.0 in 3v3, and multiplying the castle's health by the number of players changed that by only about 0.3 minutes. Matches are decided when the defenses fall, not by the castle's health bar. So the castle stays the same in every format, while the troop cap per side grows from 90 to 135 to 180. And 1v1 plays exactly as before: we checked that the simulation produces identical results.

What's missing is online play with more than two people. For now, it's you and a friend, plus AI allies.

Update, October 4: not missing anymore. See Eight People, One Battle.

— The Castle Arena team

Two problems took far more measuring than we expected: melee troops that would not fight, and troops that fly.

The soldier walking in place

When two armies met, the melee troops at the back would press against their allies' backs and walk in place, legs moving, going nowhere. Each one headed straight for the nearest enemy, usually the same enemy the soldier in front was already fighting, and the rule that keeps troops from overlapping pushed it back every step.

We measured it before changing anything. In melee fights on open ground, troops spent 26% of their combat time walking in place. In a narrow corridor it was 35%, and in ordinary matches between computer players, 9.7%.

To find a fix, we built a lab: a copy of the simulation where only the movement rule can be swapped. It staged four scenarios (open ground, a mixed army with archers, a corridor about four troops wide, and a skeleton swarm) plus full matches. A troop counted as walking in place if it walked for half a second but covered less than a quarter of the distance its speed allows. Then we tried 13 different rules.

The failures taught us a lot. "Stop if an ally is fighting in front of you" eliminated walking in place, but fights took twice as long, because nobody from the back ever arrived. Aiming for a free spot around the target barely helped: in a battle line, that ring is already full of the enemy's own neighbors. What worked was picking a target that has a free attack spot, then finding a path to it around whoever is standing still.

The winner is the patient route: a troop plans a short path to the nearest free attack position, tries to squeeze between allies, and if it gets stuck, re-plans without squeezing or waits. Walking in place fell to 5.6% in the open, 6.8% in the corridor and 1.3% in full matches. One rival rule did even better in matches (1.0%), but in the corridor its troops stood in a tidy queue and landed fewer hits than before. The patient route pushes through first, and it simply looked more natural.

Did it break the balance?

Any of these rules makes melee much stronger: with the same troops on both sides and the new rule on one side only, it won 79–100% of the fights. One Training lesson broke on the spot, with its all-melee wave suddenly too strong, so we cut it from six enemy camps to five.

In a real match, though, both sides get the new rule. So we ran every faction against every other, 1,050 matches with each movement rule on the same seeds. Faction win rates stayed in the same band (44–60% before, 42–57% after), with no faction beyond normal noise. Our first run used a lab with a small bug that made some matches differ from the real game, so we fixed it and ran everything again before trusting the answer.

Troops with wings

Some troops fly, and today every faction has at least one. A flyer goes straight over forests, water and walls and never bumps into troops on the ground. The real question is who can hit it. Melee and siege attacks only reach the ground; ranged attacks reach both. Dedicated anti-air troops like the Marksman and the Ornithopter hit flyers (and buildings, weakly) but ignore ground troops. A few units carry a second weapon, like the Steel Giant's anti-air missiles. Splash damage follows the same rules, so a catapult stone never clips a dragon.

Flight shook things up. Win rates across factions spread from 38–58% to 22–82%. The League of Gears dropped 34 points, because the troops from its most-built building were now anti-air specialists and most of the rest only hit the ground. The Bone Legion, which had no flyer at the time, dropped 20. Our own recommendation was to fix those causes before touching any numbers, and both fixes have since landed: the Rocket Bastion fires a Barrage at enemy flyers, and the Bone Legion has a Frost Wyrm. In our latest round-robin of computer players, every faction sits between 42% and 57%.

What's still provisional is how flyers look. They hover above the ground with procedurally drawn wings (membranes, feathers, faerie wings or propellers) over a shadow and a team ring. We don't have proper 3D flying creatures yet, and it shows.

— The Castle Arena team

The sky over Castle Arena is now a real one. The sun rises and sets with a warm glow at the horizon, the moon shows a different phase each match, stars twinkle at night and clouds drift with the wind.

Storms

About twenty seconds before a heavy rain, the interface warns you that a storm is approaching. The wind picks up, thunder rolls in the distance and a dark wall of clouds rises on the horizon. Online, both players get the warning at the same time.

A battlefield that remembers

• Grass gets trampled into dirt where the troops march, turning to mud in the rain and slush in the snow.
• Explosions, lightning and fallen buildings scorch the ground for a few minutes.
• Ambient sounds follow the hour, the weather and the arena: birds at dawn, crickets and owls at night, frogs in the swamp, howling wind in winter.

For comfort, Lightning flashes (normal, soft or off) and Weather effects can be adjusted in the Options.

— The Castle Arena team

Castle Arena now plays online. The host creates a lobby, for friends or public, and invites through the Steam overlay or the Invite friend button. Each player picks a faction and a perk, marks Ready, and the battle begins.

After the battle

• Rematch takes both players back to the lobby with the same faction and perk, already ready. When both ask, the next match starts on its own.
• Every match is recorded. Highlights builds a 30 to 60 second reel with the biggest fights, Rescues and falling castles.
• Clicking a point on the result charts opens the replay at that exact moment.
• Your Profile keeps your history: wins, streaks, favorite faction and results by faction, arena and opponent.

The story of how two computers stay in perfect sync is in the devlog.

— The Castle Arena team

On day one we wrote a blunt review of how the game looked. Zoomed out, troops were five to eight pixels tall and their team color lived in a thin ring on the ground; in a mirror match you could not tell which soldier was on which side. The central forest hid the entire north-lane fight. Smoke from a ruined castle looked like a pile of grey hexagons. And there was no sound at all. Most of what follows started as an answer to that list.

Six arenas, one field

Every arena keeps the same field size, castles and territories, with mirrored obstacles so neither side gets the better half. What changes is the no-man's land and the biome. River Valley is the classic, a forest splitting two wide lanes. Autumn Crossroads has two russet groves and a corridor down the middle. Frozen Lake squeezes each lane between an icy lake and boulders. Dune Canyon zigzags between sandstone mesas. Murky Swamp is a web of pools and thickets. Citadel Ring walls each base and loops a road behind both castles.

Sky, weather and storms

A full day passes in 16 minutes of play, starting at a random hour. Nights bring bluish moonlight, lamps, torches on the castles and fireflies. The sky is a real dome with a sun, a moon whose phase changes from match to match, twinkling stars and clouds drifting with the wind. Weather shifts during the match: clear, cloudy, light rain, heavy rain with thunder, ground fog and snow, which piles up on roofs and treetops.

A heavy storm never arrives unannounced. About 20 seconds ahead, the HUD warns "A storm is approaching…", the wind rises and thunder rolls inside a dark wall of cloud on the horizon. Water reflects the current sky, from the river to the rain puddles, and each arena has its own color grade that shifts with the hour and the weather while leaving team colors alone.

None of this touches the rules. The match seed sets the schedule, so both online players see the same sky.

Rare events and wildlife

The seed also rolls rare events that fit the hour and the weather: an aurora on clear or snowy nights (almost half the matches on Frozen Lake), a sandstorm sweeping through Dune Canyon, an eclipse that turns the afternoon into dusk for about 50 seconds, windblown leaves at Autumn Crossroads, shooting stars, and a rainbow after the rain.

Deer, rabbits, foxes, ducks, camels, lizards and birds live at the edges of the field. They never step onto it, but explosions, lightning and falling buildings send them running, and they wander back once things calm down. The ground keeps score too. Grass bends as troops pass, busy paths wear into packed dirt (mud in the rain), and explosions leave scorch marks for a few minutes.

Effects, HUD and the menu

Smoke, fire, sparks and spells became textured sprite effects instead of plain shapes. Buildings collapse into lingering rubble, and arrows stay stuck in the ground. The match HUD is now a set of compact dark-glass panels with gold trim: a scoreboard on top with castle health, troops, Rescues, the clock and a tug-of-war rope marking the front line, and the minimap, selection and command card along the bottom. Behind the main menu, rotating vignettes like Clash on the lane, Wings over the field and Night watch each roll factions, an arena, an hour and the weather.

Your colors, your way

The coat of arms editor offers seven shield shapes, eleven divisions, ten tinctures and 30 original charges, with more to unlock. When a charge would vanish into its field, the editor warns you and Fix it suggests a better tincture. Your arms fly on every banner you own, and victory effects like fireworks or a flock of doves unlock through achievements.

Accessibility got the same care:

• Sound captions: short texts with an arrow pointing to where each important sound came from.
• Six team color palettes, including deuteranopia, protanopia, tritanopia and a high-contrast mode with stripes, each with a preview.
• Reduced motion removes shake, trails and flashes; lightning flashes can be softened or turned off.
• Full controller support: a virtual cursor with gentle magnetism, D-pad navigation through the HUD and menus, button icons per controller, remappable buttons, and touch on Steam Deck.

— The Castle Arena team

A tug-of-war game is at its best with a person on the other end of the rope, so online play came early: Castle Arena plays 1v1 through Steam. One player creates a room (friends only, or public so it shows up in the room list) and invites someone through the Steam overlay or the Invite friend button. An invite accepted while the game is closed opens the room as soon as it launches.

In the room, each player picks a faction and a perk and marks Ready, and the host sets the match length, artillery, fog of war and arena. When the match ends, Rematch sends you both back to the room with the same picks, already ready. Once both of you ask for it, the next match starts by itself in about three seconds.

Only the orders travel

The interesting part is what does not cross the internet. A battle can have 90 troops per side, each with health, a target, a path and cooldowns. Instead of streaming all of that, both computers run the exact same simulation side by side and send each other only the orders the players give: build here, upgrade that, cast the Rescue there.

That only works if the rules are perfectly predictable. Given the same start and the same orders, two machines must arrive at exactly the same battle, down to the last hit point. So every bit of chance in the rules, like a critical strike or a dodge, comes from a shared sequence of dice rolls that starts from the same seed on both sides. An automated check fails if any rule ever takes a random number from anywhere else.

In practice, an order you give runs on both machines about 200 milliseconds later. About once a second the two computers compare a fingerprint of the whole battle, and if they ever differ, the match stops rather than letting two different games quietly drift apart. Traffic goes through Steam's relay network, so players never see each other's IP address.

When someone drops

Connections fail, games crash, computers restart. If your opponent disappears, the match pauses for you with a 2:30 reconnection countdown. You can wait one more minute at a time, claim the victory after the first minute, or leave. Short hiccups only show "Unstable connection…" while the missing turns are requested again.

The player who dropped just opens the game again and picks Rejoin match on the main menu. The computer that stayed sends a full snapshot of the battle in small, confirmed pieces, and both players carry on from there. The match's replay still comes out complete. A dedicated test drops and restores both sides and loses turns on purpose, then compares the results.

Watching, live and later

A room accepts up to four spectators, before or during the match. They get a spectator panel comparing both sides, an automatic camera and the players' emotes. The host picks a broadcast delay of one or two minutes. Zero delay is only allowed in a friends-only room, because in a public room a spectator could pass the match along to a player in real time. A "LIVE −2:00" badge shows the delay, and players see how many people are watching.

Every match is also saved as a replay. Because the battle is deterministic, a replay is tiny: the match setup, its seed and the list of orders. You can watch at 0.5x to 8x and jump around freely. Snapshots taken along the way cut a jump back in a 25-minute match from as long as 25 seconds to under a third of a second.

Highlights turns a match into a 30 to 60 second reel. While you play, a scout scores how intense every second of each lane was and notes the big moments: Rescues, buildings going down, the castle falling. Afterwards it picks varied clips and plays them with title cards and a camera that follows the fight, with the castle falling in slow motion. Save video records the reel with the game's sound and saves it to your Videos folder.

The charts on the result screen are clickable too. Click a point or a marker (✦ Rescue, ▼ building, ♜ castle) and the replay opens at that exact moment. It's the fastest answer to "wait, when did we lose the north lane?"

Team matches build on all of this. More in Many Ways to Play and, with up to eight people online, in Eight People, One Battle.

— The Castle Arena team

Castle Arena asks new players to unlearn something. Most strategy games teach you to click on soldiers, and here you never do. Explaining that in a text box doesn't work, so we didn't try. The training teaches by playing: five short lessons and a proving battle, and every one of them is a real match.

Real matches, carefully set up

Each lesson uses the same troops, buildings, combat, economy and AI as a normal game. Only the setup changes: which buildings and items each side may use, how fast the AI builds, what is already standing at the start, how much gold you have and how healthy each castle is. Nothing is scripted. The lesson just arranges the board so that one idea matters more than everything else.

• Lesson 1, The castle fights for you. The Crown against a slow Bone Legion. You build, the first troop appears at around 17 seconds, and the first fight starts near the one-minute mark. Your buildings make your army.
• Lesson 2, Counterattack. The Abyssal Pact sends only Imps, which wear Light armor. Stick with the Barracks and you trade badly: in our tests, about 95 kills for 265 losses. Switch to the Archery Range and you win and take the castle.
• Lesson 3, Gold that pays off. You start with 1,000 gold, the enemy is already producing, and if no castle falls in six minutes the higher income wins. War Drums sit in the shop as a temptation.
• Lesson 4, Wave timing. A Steppe Horde with six synced camps attacks in waves of six, and you have one Rescue. The same Rescue is worth 2 kills or 10, depending on timing.
• Lesson 5, Upgrade. Look for the golden arrow. In our tests, never upgrading won 4 of 6 matches; upgrading won 6 of 6.
• Proving battle. Normal rules, a full faction, the shop, the Rescue, a 20-minute limit and the AI on Easy. Help is down to emergencies only.

Every lesson has a "learned" way to win comfortably, while the naive way struggles or loses. We measured that with automated players, and those measurements are now automatic tests. If a future balance change breaks a lesson (say, the right counter stops speeding up the win), the test fails and we know right away.

Hints that fade

Hints show up one at a time, with an icon and a short line. They have cooldowns, can be dismissed and don't repeat. Help shrinks lesson by lesson: step by step in lesson 1, almost silent in the proving battle.

The help level isn't fixed, though. If you are struggling, meaning your castle lost more than 8% in 30 seconds, you are losing trades 1.6 to 1, your gold is piling up or your hits land for less than 90%, the hints step back up a level. If you are doing well, they step down. The counter hint is a small ladder: first it notes that your hits deal only 70% against a Light enemy and points to the badges on your buildings; if nothing changes in 30 seconds, it says Pierce deals 175% to Light and lights up the right card with a ✓. Once you own a counter, it goes quiet.

Any win completes a lesson. You can lose, retry, pause, open How to play right on the relevant topic and come back, or quit. Progress is kept.

Why multiplayer only recommends it

For a new player, Single player opens the training first, with an "I know the basics" button that goes straight to a free battle. Online, the training is only a recommendation, and it disappears once you finish. We didn't want a gate: someone who already knows the genre, or a friend who just accepted your invite, should be able to play right away.

What it doesn't teach yet

Playtesting turned up plenty: a lesson panel that swallowed clicks on the map, a Rescue that wiped out an entire wave being called "wasted", dusk lessons too dark to read the battle. Those are fixed. Some things still have no lesson: where to place buildings, spawn flags and cages, specials and legendaries, perks. All lessons use the Crown, whose attack triangle is the cleanest to learn from. Syncing didn't get a lesson either: in the current rules its effect is too small to carry one, so it shows up as an optional tool in lesson 4.

— The Castle Arena team

A strategy game lives or dies on balance, and balance is easy to get wrong when you go by feel. So we built a lab. The simulation runs without graphics, far faster than real time, and pits the AI against itself as many times as we ask, with fixed random seeds so any interesting match can be replayed exactly.

The judge

Our first big round started with three separate reviews of the game: rules, balance and interface. Then came what we call the judge, a pass that weighs the findings against each other, decides what goes in, and makes every change survive a fresh batch of AI-versus-AI matches before it stays.

The balance review simulated about 1,000 matches and found something surprising: the castle barely mattered. Once a castle dropped below 90% it was gone in a median of 0.4 minutes, and giving it more HP or doubling its attack changed nothing measurable. Matches were decided by one giant fight between two armies sitting at the troop cap. The economy was simply too fast: the build zone filled up around minute 18, with 22,000 lumber left unused and bounties making up 31% of all gold earned.

The fix was a package, not a single knob: pricier entry buildings, bounties cut to 60% of their value, and the troop cap lowered from 110 to 90. We also found a siege exploit, since leaning on siege buildings won 75% of the time; a longer spawn interval brought it down to 60%. And the judge threw out two proposed AI changes after testing them. One of them let a single faction take 16 of 17 castle victories.

Matches that never end

Then we hit the opposite problem. We ran every faction pairing ten times on the default settings, 1,050 matches in all. In 21% of them there was a stretch of 10 minutes or more with no progress at all (no castle damage, no buildings lost for good, a front line going nowhere) while both armies kept producing and trading. A typical stretch like that saw 547 troops die. Overall, 18% of matches reached the 30-minute limit, and with the limit turned off, 3.8% were still tied after two hours. One went 114 minutes without progress.

Before changing anything, we spent 3,880 matches finding out why. Three causes stood out:

• The troop cap as a wall. With both armies stuck at 90, extra gold no longer turns into pressure. Matches that peaked above 150 troops on the field became stalemates 73% of the time.
• Home-field area damage. The AI puts its spell buildings behind its castle, where they cover their own half of the field: 99% of the troops they kill die on the caster's side. Whoever pushes walks out of their own umbrella and into the enemy's.
• An AI that couldn't break a deadlock. In many factions it kept stacking defensive spell buildings in a slot it believed was artillery.

We also ruled things out: pathfinding (under 2% of troops ever got stuck), narrow maps (a chokepoint test map was the most decisive of all), healing and castle HP.

Then we put our tiebreaker on trial, replaying the timed-out matches with no limit. The current rule picked the eventual winner only 55% of the time. Income alone did worse than a coin flip, at 44%, because rebuilding a destroyed building adds income again, so the side taking the beating often earns more. Saved Rescues were right 76% of the time when they settled it. Rescues first, then net buildings destroyed, then the front line: that order got it right 68% of the time.

Evidence, cause, options

That is the discipline. Evidence first, then the cause, then a list of options, each one checked for risk. Does it keep comebacks possible? Does it punish a legitimate defense? Does it erase a faction's identity? Only then do we touch numbers, and we touch them carefully. Rewriting from scratch how the AI picks buildings made everything worse; a one-line change to the existing logic cut matches reaching the time limit from 18.1% to 11.0% without tipping the balance between factions.

As we write this, none of these stalemate fixes is in the game yet. The measurements are done, the options are on the table and the next experiments are defined. Balance is never finished, but at least now we know where to look.

— The Castle Arena team

Most of the decisions you make in Castle Arena are money decisions. Since you never steer a soldier, gold is how you play: every building is a bet, and the economy is designed so those bets keep paying, or keep costing, for the whole match.

Income, every seven seconds

Every 7 seconds both players get paid. The castle always gives 14 gold, and on top of that every building adds a share of what it cost: 2% for troop buildings, 1.8% for siege, 1.2% or 0.9% for specials and only 0.4% for towers. Items add nothing. Upgrades count too.

That income is permanent. If a building is destroyed, the income it generated stays with you. A building is an investment in your economy as much as in your army, and losing it on the battlefield doesn't take back the money you already put in.

You start with 300 gold. Bounties add more: each enemy troop you kill pays a little, and a destroyed building pays 20% of what its owner invested.

The progressive tax

Income is taxed in brackets of 25. The first 25 is untouched, and each bracket after that is taxed 10% more than the one before, up to 80%. In practice, a gross income of 30 nets 29.5, 100 nets 85, and 260 nets 142.

Why tax at all? Because otherwise whoever pulls ahead in economy simply keeps pulling ahead. The tax squeezes that gap: between two players who invest everything, income ends up very close. That moves the weight of the match back to what you build, not just how much.

It has a side effect we won't hide: when good economies converge, "higher income" becomes a weak way to break a tie at the time limit. We dig into that in the balance lab post.

Idle gold is a mistake

A troop building pays 2% of its cost every cycle, forever, and trains troops on top of that. Gold sitting in your pocket does neither. We measured it while building the training: with 1,000 gold against an enemy that was already producing, investing in troop buildings won 6 test matches out of 6. Saving won 1 of 6. Opening with War Drums or with two towers lost every time. The Drums (650 gold, +33% damage for all your troops) aren't a bad item; buying them at minute one is the classic beginner trap.

Lumber and legendary crystals

Troop buildings refund their cost as lumber (siege buildings refund 75%). Lumber is the second currency: it pays for specials, towers and legendaries. So the more army you build, the more you can afford in defenses and big plays.

Legendary crystals are the scarce one. You start with one, every legendary building uses one, and the shop sells more for 1,750 gold. If the legendary falls, its crystal comes back.

The shop and perks

The shop keeps a stock per team that refills over time. It sells permanent auras (War Drums, Marching Pipes), scrolls, the Thunder Orb, staves, the Repair Rune, a Mercenary Catapult and the two big hammers: Fury (+100% damage for 30 seconds, unlocked at 5 minutes) and Quad Fury (+300%, unlocked at 10). Items give power, never income. That is the trade.

Before the match you also pick one perk out of three drawn at random, each with a bonus and a drawback. Glass Cannon gives up to +50% damage as your troops lose HP, but costs 10% max HP. Overdrive gives +30% attack speed while it is on, and your income shrinks for as long as you keep it on.

Waves and the Rescue

Each building has its own cycle, but you can sync a building to another one with an equal or longer timer so their troops leave together, as a wave. Honestly, under the current rules syncing matters less than we expected, since troops already bunch up on the lanes.

And then there is the Rescue. You get one per match, and it kills every enemy troop in a large area. On a big wave at your gates it can be worth ten kills; thrown away early, maybe two. If it hits nothing, it comes back after 3 minutes. At the time limit, the side with more Rescues saved wins, which is why the Rescue doubles as a tiebreaker: whoever already spent their emergency button is usually the one about to fall.

— The Castle Arena team

Castle Arena is a tug-of-war strategy game, and its central rule fits in one sentence: you never command a single soldier. You put up buildings, the buildings train troops on their own, and those troops march down two lanes around the woods in the middle of the field and fight whatever they meet. Your job is deciding what to build, where, and when.

How a match works

Each side has a castle, a territory to build in and a worker. The worker is your only unit: it walks only inside your own territory, can't be attacked, raises every building, casts the Rescue and carries your items. Everything else happens because of what you built.

Every building has its own training cycle. When its bar fills, a troop comes out and heads for the enemy castle by itself. Every 7 seconds you collect income from your castle and from everything you have built, so gold put into buildings keeps paying you back. When a golden arrow appears over a building, it can be upgraded to train something stronger.

There are two ways to win. Bring down the enemy castle, or reach the time limit (30 minutes by default) holding more Rescues, the once-per-match ability that wipes out every enemy troop in a large area. If the Rescues are tied too, the higher income wins.

What the game is about

If we had to boil it down:

• Decisions, not clicks. There is no unit micro. The skill is in reading the battle and answering it with the right building at the right moment.
• Gold that works. Idle gold earns nothing. Investing early means troops now and more gold later, and we wrote a whole post about the economy.
• Counters you can read. Every troop has an attack type and an armor type, arranged in a triangle: Normal beats Medium, Pierce beats Light, Magic beats Heavy. The tooltips tell you what each troop is strong or weak against.
• One big button. You get one Rescue per match. Spend it on a huge wave at your gates and it can save the game; waste it early and you will miss it.

We are making Castle Arena for people who enjoy strategy but would rather think than race the clock with their mouse, and for anyone who likes watching a plan play out on its own.

What exists today

Castle Arena is built for Windows and Linux and is headed to Steam. Right now the game has:

• 14 factions, each with its own buildings, troops and abilities (meet them all);
• six arenas, from River Valley to the walled Citadel Ring, with day and night and changing weather;
• Single player against the AI on Easy, Normal or Hard, plus a mode to sit back and watch the AI fight itself;
• Training: five short lessons and a proving battle that teach by playing (how we built it);
• online matches through Steam, one against one, or bigger team matches where the extra seats are filled by AI allies;
• replays of every match, with an automatic highlights reel.

Controller support and a Steam Deck setup are in as well.

How we work

We test our own promises. Early on we ran 165 targeted checks against the rules; 157 passed, and each of the 8 failures became a fix. One of them was a hidden troop cap that was silently throwing away spawns in long matches, without telling anyone. Later we checked about 400 in-game texts against the real numbers behind them and corrected around 70. When a tooltip says "+33% damage", we want it to mean exactly that.

This devlog is where we explain those decisions: the economy, how we balance, how the training was built, the factions. Thanks for reading, and see you in the lanes.

— The Castle Arena team