Decomp, recomp, port: three words that are not the same thing
The vocabulary matters, because "it runs in a browser" tells you very little about how a project was built.
- Decompilation tries to turn a game's compiled program back into readable source code. The Verge describes decomps and recomps as reverse engineering that breaks a game into its building blocks. The game is then rebuilt to run on hardware it was never meant for.
- Recompilation takes code and builds it for a new target. The project index Recompiled Games says tools translate PlayStation 2, PlayStation 3 or Xbox 360 code into C or C++. That code can then build for a PC or, through WebAssembly, for a browser.
- Source ports and engine reimplementations take another route. The same index says some projects write a fresh engine that reads the original game files.
A project's description alone often won't tell you which of these it is. Several entries on that index are labelled "method not stated."
The Verge's roundup: what has happened
The Verge's coverage, as of its last update, includes these items.
- Halo in a browser. A browser build of Halo: Combat Evolved is based on OpenHaloCE. It sits alongside a decompilation-based build advertised as supporting up to 128 players across Windows, Linux and Android — a capacity the developer marked untested. The Verge's Sean Hollister notes that many people contributed.
- Lego Racers. A fan recreation called Step On It runs in desktop and phone browsers, with split-screen and online multiplayer. It also has Android, Mac, Windows and Linux builds, including for the Steam Deck.
- Titanfall 2 VR. A free mod from a solo developer who had spent about a month on it at the time of writing. Hollister rated it one of his top five VR games. That is one reviewer's hands-on opinion, not a benchmark.
- Xelee. Super Smash Bros. Melee in mixed reality. It needs a Quest 3 or 3S and a copy of the 1.02 game. The mixed-reality layer is described as AI-written, while the game itself comes from the Melee decompilation.
- Mario 64 in your room. Creator Lucas Martinic says it is built on the open-source Mario 64 decomp with help from Claude Opus 5.5. He says he will release a repository.
- Silent Hills P.T. A native PC port of the delisted demo. Users must supply their own PS4 game files.
- BlueWake. A static recompilation of Wind Waker that is described as running on iOS, Mac and Windows.
- Half-Life: Alyx on Vision Pro. It is credited partly to Valve's ARM port for the Steam Frame and partly to help from Claude.
- Switch 2 jailbreak. The roundup also reports a Switch 2 jailbreak that used OpenAI's Codex. It is software-only and tethered, so it has to be run every time the console starts.
Treat these as time-sensitive. Availability, platform support and file requirements can change quickly.
What "plays in a browser" can actually mean
The Recompiled Games index, last link-checked October 24, gives a useful snapshot. It listed 39 projects, 36 working links and 23 multiplayer entries. The entries are a mix of WebAssembly builds, source ports and static recompilations. Examples include The Simpsons: Hit & Run as WebAssembly and WebGL, and Quake III Arena through ioquake3 compiled to WebAssembly.
It is a directory, not an audit. But it flags a practical point: entries are tagged "instant," "own files" or "unknown." Some browser projects need you to supply game files from your own copy, and Halo: Combat Evolved is one of them on that index. Others load instantly.
If a browser port stutters
The index offers one troubleshooting tip that applies to Chrome. Most browser ports draw using WebGL or WebGPU, which relies on the graphics card. With acceleration off, the browser falls back to the processor and frame rates drop sharply. The index's steps are:
- Paste chrome://settings/system into the address bar.
- Find "Use graphics acceleration when available" and switch it on.
- Click Relaunch. The change only takes effect after Chrome restarts.
- To check, open chrome://gpu. WebGL should read "Hardware accelerated."
The index also lists battery-saver mode, a laptop falling back to its weaker built-in graphics, and many open tabs as slowdown causes. These steps come from that index and are scoped to Chrome. We haven't tested them.
The Microsoft angle: Xbox Labs
This is where the story becomes Microsoft news. Microsoft has formed "Xbox Labs" in response to the recent explosion in AI game modding and recompilations. The Verge's Tom Warren reported the news on October 13. In the Verge's account, Xbox CEO Asha Sharma describes a small group of game makers, engineers and scientists. Their job is to turn emerging ideas into things players and developers can experience.
Other outlets added detail.
- Sharma asked Scott Van Vliet, Xbox's chief technology officer, to lead the group.
- The group has its own site at labs.xbox.com. Shacknews reports that visitors can register an email address for updates.
- VideoCardz reports that Sharma made clear Microsoft remains committed to protecting its games and associated communities. The same outlet says what this means for unofficial ports and fan projects remains unclear.
- TrueAchievements observed that Sharma left any mention of "AI" out of her post. That is the outlet's interpretation of her wording, not something Microsoft has said.
That mix is the interesting tension. Microsoft owns Halo and Call of Duty, two of the franchises appearing in these projects. It is simultaneously saying it will protect its games and saying it wants to learn from what the community builds. Which of those wins out is unknown. Nothing in the reporting says what Xbox Labs will ship.
AI is the accelerant, and the community is feeling it
The Verge's Andrew Webster argues that AI coding tools have cut the timeline of decompilation sharply. A group once spent years decompiling the original Animal Crossing on the GameCube, for instance. But he also says the surge is straining communities dedicated to careful preservation.
Several reactions illustrate the friction.
- decomp.dev announced on October 15 that it is sunsetting its public index and leaderboard. It said the site had turned decompilation into a "hollow numbers game." It blamed people who burn tokens to push progress numbers or to "port game to PC."
- Digital Sun is keeping the playtest for its indie vampire game ReVamp private. It cited worry about games being reverse-engineered and cloned before release.
- Anthropic added a rule to Claude Code's system prompt to stop it recreating specific existing games. The Verge reports that the rule also fired when users merely named a game to describe mechanics. Anthropic said version 2.1.317 fixes this. You can name a game to describe what you want, and Claude should build an original game in that genre. If you ask for a copy, it offers something similar instead.
That Anthropic change is a product-behavior tweak. It is not a legal ruling, and it doesn't guarantee that generated work avoids infringement.
The legal gray area
The Verge says these unofficial versions may sit in a legal gray area. The Recompiled Games index is blunter about the risks. It says rebuilding a game can copy protected code, and posting the result may infringe even if no game files ship. It says projects that stream assets or rebuild a current commercial game carry the most risk. Ports that need your own copy, or use an engine its owner released as open source, are on firmer ground. It adds that treatment differs between countries and is largely untested in court. That is one directory's general view, not legal advice.
What this means for Windows users
- Know what you're downloading. Native Windows builds from GitHub projects are unofficial. Check what the project says it needs from you and where its code comes from.
- Expect to bring your own files. Many projects require game data from your own copy, as the P.T. port and Xelee do.
- Watch the usage claims. PC Gamer, as relayed in the research notes, reported the Halo browser site briefly went down under heavy traffic. The developer said almost 20,000 games were played in the first five hours. That figure is self-reported.
- Watch Xbox Labs. If Microsoft turns this energy into official tooling, it would affect game developers who build for Windows and Xbox.
Bottom line
Game reverse engineering has moved from a patient hobby to a fast-moving, AI-assisted scene. It has produced impressive technical feats and a real backlash from the people who made preservation their craft. Xbox Labs is Microsoft's first public answer, and so far it is a statement of intent rather than a product. The details of how it handles the copyright question will matter more than the announcement did.
Correction (November 5, 2026): The Halo browser entry originally described the decompilation-based build as supporting 128 players. The developer's own announcement listed that figure as "up to 128 players (untested)", so the text now reflects that it is an untested claim, not a demonstrated capacity.