Hadron runs Windows Steam games on Apple Silicon, no Rosetta

Apple has been telling Mac gamers “soon” for about fifteen years now. Meanwhile, a solo developer just shipped Hadron, a tool that lets you install Windows games from your Steam library on an Apple Silicon Mac with no Rosetta involved at all. Open source, free, and roughly 250 commits old. I love this timeline.

If you’ve used Proton on Linux or the Steam Deck, you already understand the idea. Hadron registers itself as a Steam Play compatibility tool inside the regular Mac Steam client. You click install on a Windows game, Steam hands it to Hadron, and the game runs. Its README pitches it bluntly: “It is to the Mac what Proton is to Linux, and an open-source alternative to CrossOver for Steam games.”

Hadron: Windows games on Apple Silicon without Rosetta

The clever bit is what’s missing. Every other Windows-on-Mac solution I know of (CrossOver, Whisky, Apple’s own Game Porting Toolkit) leans on Rosetta 2 to translate x86 code. Hadron doesn’t. Wine is compiled natively for arm64, and the x86 instructions of the game itself are translated by FEX, the same emulator the Linux ARM crowd has been polishing for years. Graphics calls go straight to Metal: mtld3d for Direct3D 9, DXMT for D3D10 and 11, vkd3d-proton on top of KosmicKrisp (Mesa’s Vulkan-on-Metal driver) for D3D12, and Zink for OpenGL.

Why does that matter? Because Apple is pulling the plug. The LinuxFr write-up that got me looking at this reminds us that macOS 28, due in 2027, will strip Rosetta 2 down to a stub for “older unmaintained gaming titles”. Everything built on Rosetta is living on borrowed time. Hadron is built from free software “from floor to ceiling”, as the author of that piece puts it, and owes Apple nothing.

What actually runs today

Let’s be honest about the state of things. The README says it plainly: “Hadron is in early development. A handful of games play well and many don’t start yet.” Portal and Portal 2 play fully. Subnautica, Astroneer, Among Us (online login included) and Geometry Dash run well. Teardown runs but is held back by CPU translation. Slay the Spire won’t start, and Subnautica 2 chokes because Metal’s shader compiler gives up on its biggest compute shaders. Kernel-level anti-cheat? Forget it. Third-party launchers? Same.

Still, the project moves fast. The LinuxFr author tested Unvanquished, hit two bugs, and both were fixed within two days. A release followed inside a week. That’s the kind of responsiveness you never get from a company that treats Mac gaming as a keynote slide.

One more detail that’ll make some people grumble: most of Hadron’s code was, per its own README, written by Claude Code running Claude Opus 5.5, with developer David Andrews directing and testing. Make of that what you want. I’d rather have a working arm64 Wine pipeline that a bot helped write than another decade of waiting. (Linus had some nuanced thoughts on AI patches recently, and this seems to be the “pro who tests their stuff” end of that spectrum.)

Installing Hadron on your Mac

You’ll need macOS 27 on Apple Silicon and Steam for Mac. Then brew install --cask broyojo/hadron/hadron, or grab the disk image from the GitHub releases. Open Hadron, pick “Set up Steam”, go allow it under Privacy & Security when macOS predictably panics, and run setup again. Be aware that setup re-signs Steam.app with its own signature instead of Valve’s, which is a legitimate thing to think twice about. First launches are slow because the Windows environment gets built and shaders compiled. There’s no telemetry; the only call home is a GitHub version check.

Would I bet my evening on it? For Portal, absolutely. For anything competitive, not yet. But the direction is right, the license is BSD-3, and it doesn’t depend on Cupertino’s mood.

Apple spent years saying Macs could game. Turns out one person and a compiler got there first.