AI Decompilation Enables Browser Ports of Halo, GTA: Vice City, and The Simpsons That Run Well

In the past couple of weeks, hundreds of vibe-coded, AI-decompiled emulators and games have appeared online seemingly out of thin air. The reason is Claude's latest update, Claude Opus 5.5, which is reportedly extremely good at decompiling. A game's source code can now be compiled and reconstructed in record time, something that used to take coders months to achieve. The so-called native Fallout and Call of Duty: Modern Warfare ports, along with AI-generated Super Mario 64 mash-up mods inside Elden Ring, are direct results of this new capability.

The Ports Actually Run Well

The most concerning development, according to Kotaku reporter Lewis Parker, is that AI-decompiled web browser ports of Call of Duty: Black Ops, Halo: CE, Grand Theft Auto: Vice City, Skate 3, and The Simpsons: Hit and Run seem to run very well. After playing through a number of the web browser ports, some of them appeared to be borderline flawless. The Simpsons: Hit and Run might even be better than flawless, as it reportedly targets 240fps.

Working Online Servers

One of the four different web browser ports of Halo: CE that was tested had working online servers, with low ping. The ports are not just visual curiosities but functional recreations of the original games, including their online play.

Why Browsers Can Handle These Games

Most of the games being ported to browsers are PS2 or PS3 era titles. The PS3 had about 512 megabytes of RAM, while a modern web browser can easily use 1,200 megabytes or more. Browser ports have not been limited by RAM usage for quite some time. The difference now is that Claude Opus 5.5 is an AI that can be left running overnight to decompile a game, instead of painstakingly working through the code by hand.

A Legal Whack-a-Mole Problem

Lawyers for publishers such as Take-Two and Microsoft can send cease-and-desist letters and get these ports taken down. But the ports were clearly easy and fast to create, so it is unclear what would stop people from simply vibe-coding another version. The situation has been compared to IP protection whack-a-mole on a scale not seen since the advent of pirated DVDs. Video game publishers' legal teams are expected to be working overtime for the foreseeable future.

Sources: kotaku.com