Steam adds Proton, making Windows games playable on Linux (at least in theory)

Last week we wrote about Valve potentially folding support for a WINE-style compatibility wrapper into Steam, allowing Linux machines to play Windows games with minimal hiccups. Now it’s a reality. Valve’s Pierre-Loup Griffais made the announcement on the “Steam for Linux” group today.

The forum post is long and very detailed, and if you’re personally invested in Linux gaming it’s probably worth a read. Here’s the highlight though, direct from Griffais:

“Today we are releasing the Beta of a new and improved version of Steam Play to all Linux users! It includes a modified distribution of Wine, called Proton, to provide compatibility with Windows game titles.”

So not just a WINE-style compatibility wrapper, but a fork of WINE itself. You can find it on GitHub, and as I theorized last week, it’s a wrapper focused on games in particular. Valve claims it’s based on Vulkan, and touts improved full-screen support, controller support, and better performance in multi-threaded games.

It’s a work in progress though. Writes Griffais, “This goes hand-in-hand with an ongoing testing effort of the entire Steam catalog, in order to identify games that currently work great in this compatibility environment, and find and address issues for the ones that don't.”

The list of currently-supported titles is short, but includes some noteworthy standouts like the 2016 Doom, Google Earth VR, Tekken 7, Mount & Blade, NieR: Automata (which doesn’t even run great natively on Windows), and Into the Breach. Then there's a grab-bag of miscellaneous titles, like 2005’s Star Wars: Battlefront 2 and Tropico 4, a.k.a. not even the latest Tropico.

Those who want to break out of Valve’s carefully marked sandbox can flip an override switch and theoretically run any game with Proton, though as last week’s code deep dive noted: This “may not work as expected, and can cause issues with your games, including crashes and breaking save games.” Not sure if that error message pops up in the current Steam Linux build, but I hope it does.

Regardless, it’s (theoretically at least) a huge step forward for Linux gaming. WINE’s always been a bit cumbersome to use, so having it built right into Steam—and with Valve actively confirming games will work—should remove some of those barriers. In the absence of Linux ports, Proton sounds like the next best thing.

Alas, Mac gamers are being left out in the cold. From the FAQ: “While Wine and Proton work on macOS, there are no plans to support the new Steam Play functionality on macOS at the moment.” Keep your fingers crossed, I guess.