A Mario-style platformer built to show off a modern web-game stack:

Vite + TypeScript (strict) + PixiJS v8 (WebGPU-first) + miniplex ECS + zustand + React HUD overlay

All art is generated procedurally at boot (pixel grids + canvas) — zero binary assets in the repo.

npm install
npm run dev        # http://localhost:5173
npm run build      # typecheck + production build
node scripts/smoke-test.mjs   # headless boot & gameplay test (needs Chromium)

src/
├── main.tsx                  # boots Pixi (WebGPU → WebGL fallback) + React HUD
├── state/store.ts            # zustand: score/lives/level/screen — meta-state only
├── ui/                       # React: HUD, pause menu, level select, debug panel,
│                             #   touch controls. Subscribes to zustand. Zero React
│                             #   in the game loop.
└── game/
    ├── Game.ts               # fixed-timestep loop (1/60s accumulator) decoupled
    │                         #   from render; interpolates positions between ticks;
    │                         #   hit-stop; level lifecycle; post-processing
    ├── context.ts            # Ctx — the service bag every system receives
    ├── ecs/                  # miniplex world; components: Position, Velocity,
    │                         #   Collider(AABB), Sprite, PlayerControl, EnemyAI,
    │                         #   Health, Collectible, Platform, Pipe, Checkpoint, Light
    ├── systems/              # input, physics, collision (in physics.ts), platforms,
    │                         #   ai (FSM per enemy type + 3-phase boss), interactions,
    │                         #   camera, animation, render, debug
    ├── level/                # LDtk JSON schema types + loader + entity spawner;
    │   └── data/*.json       #   3 sample levels as LDtk-schema JSON (IntGrid
    │                         #   collision layer + Entities layer)
    ├── fx/                   # GPU particles (ParticleContainer, 500+ poofs),
    │                         #   custom GLSL+WGSL shaders (vignette, palette swap),
    │                         #   erase-blend 2D lighting, tweens
    ├── gfx/                  # procedural pixel-art textures + parallax builders
    └── input/                # keyboard + Gamepad API + touch, edge-buffered

• Coyote time 100 ms, jump buffer 120 ms, variable jump height (release to cut), asymmetric gravity (1.6× falling)
• Corner correction — clipping a ceiling edge by ≤5 px nudges you around it
• Squash & stretch on jump/land/stomp, hit-stop 60 ms on stomps (more on boss hits)
• Camera: deadzone box, velocity lookahead, trauma-based screen shake (shake = trauma², decays over time)

• WebGPU-first (preference: "webgpu"), automatic WebGL fallback — custom filters ship both WGSL and GLSL
• Bloom (pixi-filters AdvancedBloom) on collectibles + sparkles, custom vignette, optional CRT shader (toggle in pause menu)
• Palette-swap fragment shader recolors enemy tier variants (tier 2 = blue elite, tier 3 = red brute) from one texture
• GPU particles via Pixi v8 ParticleContainer — dust, sparkles, coin bursts, 500+ particle death poofs, boss shockwaves
• 4-layer parallax (sky 0 / far 0.2 / near 0.5 / world 1.0) with per-theme backdrops
• Dynamic 2D lighting in the cave: screen darkness rendered through an AlphaFilter with erase-blend light sprites punching soft holes, plus additive glow sprites

• 3 levels (Green Hills → Crystal Cave → Castle Keep) authored as LDtk-schema JSON (src/game/level/data/); regenerate with node scripts/generate-levels.mjs
• Enemies: walker, flyer (sine hover), shell-kicker (stomp → shell → kick, shells mow down enemies) — one FSM per type
• Question blocks (coins + mushroom power-up; big players smash bricks), pipes as level warps (hold ▼), moving platforms that carry you, checkpoints
• Boss with a 3-phase FSM: jump-shockwaves → charges + minion summons → enraged everything, stomp it 9 times