The Original ‘Halo’ Is Now Playable in Web Browsers With Multiplayer Support

If you’ve been on X over the last few days, you’ve probably noticed that things have gotten very weird when it comes to modded video games. There are clips of Call of Duty operators doing kickflips and other tricks from Skate, people playing Black Ops 1’s zombie mode in Skyrim, and Miles Morales swinging through Gotham. Here’s another to add to the list: someone has gotten the Xbox version of Halo: Combat Evolved running in a web browser with multiplayer and split-screen support.

Software developer Mitchell Hynes is behind bringing Halo to web browser. As he posted on X, this version of the game features split-screen co-op and multiplayer of up to 128 players. He’s currently running a Cloudflare-powered website to host the port— which is the original Xbox version of Combat Evolved, not Gearbox’s maligned PC release — and he included the link to the site in a reply to his original post. According to Hynes, 20,000 people played the web browser port in its first five hours.

What made this unofficial port possible?

The simple explanation for why everyone’s social media feeds are suddenly full of browser ports and hallucinatory mash-ups is that there’s a new version of Claude that makes creating these much easier. Because of AI, modders can decompile games (a process that gives access to the games’ original source code) much faster than before, making it easier to bring them to web browsers and other platforms (also through AI, ususally). Halo: Combat Evolved was recently decompiled for the first time, and while the associated GitHub page doesn’t confirm whether AI was involved in this process, the project’s Discord channel is full of references to Claude.

As for the game mash-ups surfacing on social media, many are using LLMs like Claude Opus 5.5 with a specific universal-modder plugin. “Point Claude at any game. Skills, tools and the fal MCP that let Claude Code mod almost any PC game you own: recon, reverse engineering, fal-generated art/3D/audio, in-game testing, showcase videos,” the tool’s description reads.

Of course, this situation comes with plenty of moral, legal, and technical pitfalls. As existing tech experts have pointed out, these decompilations and mods are more likely to be full of bugs because they were created through vibe coding. In response, X user Funky90sLion created a list of existing decompilation projects handled by humans.

As for legal issues, many publishers likely aren’t happy to see their games used in these mashups, even if the modders acquired the original games legally. Then there’s the fact that using Claude to create these mods comes with the technology’s typical ecological and ethical concerns. And while these mods make for good social media clips, they’re tech gimmicks compared to the more authored experience offered by the original games. As with all cases of AI used for “creative” purposes, the end result is always a remix built on existing work that was pulled into the AI’s dataset, generally without the creator’s permission.

For Halo: Combat Evolved in web browsers, it’s fair to expect Microsoft will eventually take action against the unsanctioned port, which, at the time of publishing, is still playable. Xbox previously released Halo: Combat Evolved Anniversary, a remaster of the original game, and then ported it to PC through Halo: The Master Chief Collection. Earlier this year, Xbox released Halo: Campaign Evolved, a full remake of the original game’s story mode with additional missions.