For decades, if you wanted to play Call of Duty or Halo, you needed a console or a PC with decent hardware. But recently, a flood of vibe-coded games has been appearing online. What's happening here? It turns out that recent AI updates--like the release of Claude Opus 5.5--are making it very easy to reverse-engineer the source code for a game and get it running in a browser. So far, retro games from the 2000s and early 2010s are making the rounds, and if you're wondering just what the heck is going on, you can read our breakdown of why video game publishers are sweating buckets right now.
What are vibe-coded browser ports?
You've probably heard of vibe-coding by now, as this generally involves a person tasking an AI agent with generating, refactoring, and gluing code back together. I'm simplifying things here, but essentially, you tell the AI what you want, and it'll then write the code for you, as well as provide fixes. A vibe-coded browser port is essentially a video game that has been decompiled and then made playable on a website using AI; instead of downloading a massive file or installing an emulator to play the game, you just click a link, and you can start playing a game in your browser. So far, people have used AI to create all kinds of browser ports, ranging from classic console games to mash-ups of recent titles.
How are they being made and reverse-engineered?
Traditionally, reverse-engineering a commercial game required multiple steps. You'd need to use toolsets to disassemble and decompile games, analyze them, unravel rendering pipelines, and rewrite the logic behind them for a target platform, like a PC. With AI, this process has been accelerated significantly, as large-language models (LLMs) excel at pattern recognition and AI agents can take the raw, messy computer code from an old game disc or file, translating it into modern web languages. WebAssembly is a popular choice, as it allows web browsers to quickly run intensive programs.
This process also helps with addressing bugs, as memory leaks, frame drops, or audio stutter can quickly be fixed. While it's a gross simplification, the overall idea is that a creator can paste the error-message code into the AI and command it to rewrite the broken code, thus fixing the bug.
How can one person do what used to take a whole team years?
To be fair, creators and hobbyists have access to decades of emulation research to assist their own work, so they aren't exactly starting from scratch and hitting the "Make Viewtiful Joe playable on Chrome" button. Thanks to various emulation research initiatives being open-source, the building blocks for these projects are right there and waiting to be superglued back together with AI into a functioning native port. A task that would take a programmer weeks to do--like fixing memory errors--can now be done in far less time. That raw data is being used to not emulate games in browsers, but rather run them natively in a browser.
It's also worth noting that older consoles had very little memory in their hardware configurations, especially compared to today's laptops and phones. Modern browsers are powerful enough to run older games smoothly without extreme optimization.
What are some notable examples?
While new examples are popping up every day, so far, numerous well-known games have been reverse-engineered to run in browsers: classic Call of Duty games like the first Black Ops Zombies mode and Modern Warfare 2, The Simpsons: Hit & Run, old-school Grand Theft Auto games, and even Halo: Combat Evolved. As you can see in the videos embedded above, other projects have also combined elements of distinct games, such as mashing up Minecraft and Elden Ring.
How good are they?
This is probably the worrying part for developers and publishers, because many of these ports are running shockingly well. We're seeing PS2, GameCube, and Xbox-era ports running at a respectable 60fps on mid-range laptops and PCs. Usually, tracking down abandonware would involve sitting through installation menus, downloading ISOs, setting up emulators on your PC, and configuring controller plugins. But with these browser ports, you can start playing in seconds.
These aren't flawless ports; audio buffer synchronization and shader issues pop up, and mobile-browser touch controls are a pain to use. But as a proof-of-concept? They're making a name for themselves as casual play experiences that are almost identical to the original games.
How are Microsoft, Sony, and Nintendo reacting?
Game publishers are taking an active role in trying to shut down websites hosting these browser ports, but right now, it's a game of cat-and-mouse. Web developers are being clever, as to avoid being sued, they host only the recompiled code for the game, not the actual copyrighted game files you can use to get your own version working.
Rights holders have started issuing takedowns (DMCAs) in an effort to pull the websites offline and remove the code in question from internet archives, but the genie might be out of the bottle on this one.
When one website goes down, it's not long before a creator can use AI to quickly rebuild and re-upload a game on a new website. Companies will continue trying to stop the proliferation of these ports, but with AI making it so easy to rebuild them, they're facing an uphill battle.
Xbox appears to be aiming to get ahead of the curve, as it announced Xbox Labs recently. Even if the announcement for Xbox Labs doesn't mention AI, the text heavily suggests that Xbox is experimenting with building its own browser ports currently. "These experiments challenge long-held assumptions about our industry: the tether between software and hardware, the boundary between creation and play, and how people discover and experience games," Xbox boss Asha Sharma wrote.
At the same time, the deluge of AI decomps is having a negative effect on hobbyists in this space. The site Decomp.dev is shutting down thanks to “bad actors” in the scene rushing projects to completion with AI, and other experts are also warning companies to pay more attention.
“This new wave of decompile-and-port is definitely something that developers and publishers need to take seriously,” Luke Dicken, Take-Two’s former head of artificial intelligence, said to Kotaku. “It strikes me as noteworthy that this is being enabled by the subsidization of GenAI costs by the frontier labs, so this is an artificially enlarged problem right now, but it’s not one that’s going away, even if it might reduce in scale when the AI bubble pops.”
But for other big names in the games industry, these browser ports represent a serious threat to how they've traditionally done business. Historically, publishers have controlled the life cycle of every game they've created and owned. From discounts to remasters, that control is on the verge of being shattered by vibe-coded browser ports. Rogue ports undermine the careful planning behind re-releases and remasters and threaten active subscription models, and legal teams are scrambling to close legal loopholes.