Gauntlet: Depths of Doom

Arcade-style Gauntlet clone with roguelike dungeon generation, up to 4-player local co-op, written in vanilla JavaScript on an HTML5 Canvas. No build tools, no dependencies — just open index.html.

Running

# any static file server works; two easy options:
python3 -m http.server 8000
# or
npx --yes http-server -p 8000

Then open http://localhost:8000. Opening index.html directly via file:// works for most browsers too.

How to Play

Each run drops you into a procedurally generated dungeon. Kill enemies, grab loot, find the exit tile — all living players must stand on it to descend. Difficulty scales with floor depth. Shop appears between floors; run ends when every player is dead.

Controls (up to 4 players)

Player	Move	Attack	Special
P1	WASD	Space	Q
P2	Arrow keys	Enter	Right Shift
P3	IJKL	U	O
P4	Numpad 8/4/5/6	Numpad 0	Numpad Enter

Classes

Class	HP	Speed	Damage	Armor	Attack	Special
Warrior (Thor)	800	90	30	5	Melee	Shield Bash
Valkyrie (Thyra)	650	110	20	4	Melee	Shield Block
Wizard (Merlin)	400	100	35	1	Ranged	Nova Blast
Elf (Questor)	550	140	18	2	Ranged	Rapid Shot

Enemies

• Grunt — basic melee fodder
• Ghost — phases through walls
• Demon — ranged projectiles, heavy damage
• Sorcerer — ranged + teleports
• Lobber — arcing projectiles
• Generators — spawn enemies until destroyed (capped at 6 concurrent children, 180 global)
• Death — invulnerable stalker that appears from floor 5 onward, drains HP on contact, despawns after ~25s

Loot

Items drop in four rarities (common / uncommon / rare / legendary) across four slots: weapon, armor, boots, ring. Also pickups for food (heal), potions, keys (unlock doors), and gold (currency in the between-floor shop).

Architecture

Single HTML page, 18 JS modules loaded as classic <script> tags — no modules, no bundler. Files share globals defined in state.js and constants.js.

index.html              entry point, canvas 800x600, loads scripts in order
js/
  constants.js          tile types, class defs, controls, rarity tables
  state.js              mutable globals (gameState, players, enemies, ...)
  main.js               requestAnimationFrame loop, dispatches by gameState
  input.js              keyboard handling, clearJustPressed
  update.js             per-frame update for 'playing' state
  render.js             all drawing (~49KB — largest file by far)
  map.js                procedural dungeon generation, rooms + corridors
  pathfinding.js        BFS distance maps for enemy AI
  entities.js           spawn items/enemies, createEnemy, createPlayer
  enemies.js            enemy/generator/death-entity AI
  combat.js             player attacks, damage, knockback
  projectiles.js        projectile physics
  particles.js          visual particles
  juice.js              screen shake, hit-stop, damage numbers
  loot.js               loot generation and stat rolls
  audio.js              WebAudio sound effects
  gameflow.js           floor exit, advance, game-over, camera
  warnings.js           on-screen warning banners (e.g. "DEATH HAS ENTERED")

Game states

main.js is a plain state machine:

title → charselect → playing ⇄ shop
                           ⇄ lootscreen → (advance floor) → playing
                           → gameover

Each state has its own update* and render* function.

Adding a new class

1. Add an entry to CLASS_DEFS in constants.js (stats, color, special name/cooldown).
2. Add the key to CLASS_KEYS.
3. Wire the special into combat.js if it does anything beyond the generic attack.
4. Add any class-specific rendering in render.js.

Adding a new enemy type

1. Add a base stat block to the base object in createEnemy (entities.js).
2. Add it to the spawn-roll in spawnEnemies (same file).
3. Add rendering in render.js.

Tuning Knobs

Most numbers live in constants.js and the base / CLASS_DEFS objects in entities.js and constants.js:

• TILE, MAP_W, MAP_H — tile size and dungeon dimensions
• GEN_GLOBAL_CAP, GEN_CONCURRENT_CAP — enemy spawn caps
• diffMult in spawnEnemies / createEnemy — per-floor scaling (+30% count, +25% stats per floor)
• Death entity triggers at floor 5 after 30s idle

License

No license file. All rights reserved unless the author says otherwise.