Don't Fall

Real-time, server-authoritative multiplayer arena game. Move across a floating grid of tiles that shake then fall; dash to bump opponents off the map. Last player alive wins. Backend is Deno; frontend is HTML + ES Modules with Three.js. 2–8 players per room, no bundlers required.

Quickstart

Requirements: Deno (latest stable).

Start the server:

deno run -A backend/server.ts

Then open http://localhost:8000/ in a browser. Optionally pass a room with ?roomId=custom. Health check at /health. WebSocket endpoint at /ws?roomId=.

Controls: Arrow keys to move, Space to dash.

Backend (brief)

Single-process, server-authoritative simulation that also serves the static frontend.

• HTTP: serves files from frontend/ with entry at frontend/index.html
• WebSocket: upgrade at GET /ws?roomId= for gameplay
• Health: GET /health
• Loops: fixed tick TICK_RATE for simulation and STATE_SNAPSHOT_RATE for snapshots

Key files:

• backend/server.ts
• backend/game.ts
• backend/messages.ts
• backend/types.ts
• backend/config.ts
• backend/leaderboard.ts
• backend/utils/time.ts

See details in backend/README.md.

Frontend (brief)

Single-page client using Three.js, ES modules, and light prediction/reconciliation. Connects via WebSocket to the backend.

Key files:

• frontend/index.html
• frontend/main.js
• frontend/net.js
• frontend/render.js
• frontend/input.js
• frontend/ui.js
• frontend/touch.js
• frontend/constants.js

See details in frontend/README.md.

Project structure

• backend/ — HTTP + WebSocket server, simulation, validation, leaderboard
• frontend/ — HTML + ES modules client
• SPEC.md — product and technical specification
• README.md — this document

Development

• Run tests:

deno test -A backend/game_test.ts

• Server constants live in backend/config.ts and are mirrored client-side in frontend/constants.js. The server remains authoritative.
• Edit frontend files and refresh the page; no build step needed.