A developer named Mitchell Hynes has put the original Xbox version of Halo: Combat Evolved in a web browser, complete with split-screen co-op and multiplayer support for up to 128 players. He runs the port on a Cloudflare-powered website, and he says 20,000 people played it in its first five hours.
The trick is AI. New versions of Claude, an AI system, now speed up decompilation, the process that pulls apart a game’s code. That lets modders build ports faster than before. Halo: Combat Evolved was recently decompiled for the first time, and the Discord channel for the project is full of references to Claude.
Modders are also using large language models like Claude Opus 5.5 with a universal-modder plugin. The plugin’s description says it lets Claude look at any game, learn its rules, and build mods from scratch — recon, reverse engineering, generated art and audio, testing inside the game itself.
What the Port Does
Hynes’s version of Combat Evolved plays in a web browser. It supports split-screen co-op, and multiplayer for up to 128 players at once. The port is the original Xbox version, not the Gearbox PC release that fans have criticized.
The game is still playable as of writing.
| Feature | Description |
|---|---|
| Platform | Runs in a web browser |
| Split-screen co-op | Supported |
| Multiplayer | Up to 128 players |
| Source | Original Xbox version of Combat Evolved |
The Risks and the Limits
This kind of work comes with problems. Existing tech experts have pointed out that mods built through AI-assisted decompilation are more likely to be full of bugs because they were created through “vibe coding,” a term used to describe code written by machines that mimic human coding styles without always understanding what they are building.
There are also legal questions. Publishers may not want their games used in these mashups, even if the modders bought the original games legally. And using Claude to create these mods brings the usual worries about how AI systems treat data — they are trained on existing work that was pulled into their datasets without permission from the creators.
On top of that, these mods are tech tricks compared to the original games. They remix existing work rather than build anything entirely new.
Our Take
The port is a clever piece of work. It shows what AI-assisted decompilation can do right now. But it is a demo, not a finished product. The bugs are likely, the legality is unclear, and the experience is a copy of a game that already exists.
Still, it is fun to watch. The fact that 20,000 people touched it in five hours tells you something about how curious people are about what AI can do with games. This is the kind of project that makes people stop scrolling and look at a browser window.
Microsoft has released official updates to Combat Evolved before, including Halo: Combat Evolved Anniversary, a remaster, and Halo: Campaign Evolved, a full remake of the original campaign. Neither of those are browser ports, and neither are free. Hynes’s version is neither official nor paid.
It will be interesting to see how long this version lasts before Microsoft decides whether to take it down. For now, the port remains playable.
See the video the story is built around at Polygon.
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