About Mars Rally Championship
A full 3D rally racing game that runs entirely in your browser — no install, no account, no paywall. Rally stages on terrain sculpted to Martian morphologies, online multiplayer, a global leaderboard, and a physics simulation honest enough to replay bit-for-bit.
Why the browser?
Because the start line should be one click away. Mars Rally Championship loads like a website and drives like a sim: WebGL rendering with real-time post-processing, a per-wheel tire model running at fixed substeps, dynamic resolution scaling that adapts to your hardware, and touch, keyboard, and gamepad support. Phones, laptops, school computers — if it runs a modern browser, it runs the championship.
The simulation-first bet
The game's core decision is determinism. The physics steps at a fixed 60 Hz on every screen, the world is the same for every pilot, and every input is recorded — so any run can be rebuilt bit for bit from its inputs alone. That single property powers the features that matter: a global leaderboard that re-simulates every time before posting it, replays rebuilt from the inputs, downloadable rivals, a rival ladder that always gives you a beatable target, and lag-proof online multiplayer.
A living game
Beyond the Mars Cup there's a daily challenge with streaks and quests, a garage of earnable cosmetics, 30 achievements (5 of them hidden), and a voice co-driver calling pace notes. Every open stage also has a storm variant, run in a full dust storm from the start line to the finish.
New stages arrive the same way the first ones did — charted route by route in an in-house level editor, a development tool rather than a feature of the game.
Made for pilots, not accounts
There is nothing to sign up for. Personal bests live in your browser; submitting to the global leaderboard takes a call sign, not an email. The game is free and stays free.
New stages, physics changes and daily-challenge results get posted as they land — follow @marsrallychamp on X to see them first, or read the changelog.
Open-source software
The game stands on open-source code, and on the people who write it:
- three.js (MIT) draws the 3D world.
- The Colyseus client (MIT) carries the online races.
- supabase-js (MIT) talks to the leaderboard.
- Mediabunny (MPL-2.0) writes replay videos.
- FFmpeg's AAC encoder (LGPL-2.1-or-later), compiled to WebAssembly by Mediabunny, gives a replay video its sound where the browser can't encode AAC itself. It ships unmodified: read its license, get the FFmpeg source (libavcodec 62.23.103), and see how Mediabunny builds it.