The Steam Proton initiative, operated as a collaboration between Valve and the open-source community around the WINE Windows compatibility layer for Linux, is a mechanism for playing games designed for running on Windows, on Linux. Some games work flawlessly, some games are totally incompatible, and others run with minor issues. Often the stumbling block for getting games running correctly are things like DRM mechanisms that are not compatible with Proton, anti-cheat technology implementations that detect Proton as unauthorised tampering, or use of unsupported APIs, plugins or engines.
Back in 2018, when Steam Proton first officially launched, the prior game in the series, Doom , was one of the first handful of games officially supported by Proton, and easily one of the biggest and most technically demanding games in the lineup. It was reliant on the at the time newly implemented Vulkan graphics API support that id had just added to the game. Remarkably, not only did Doom  run smoothly via Proton, but on many hardware configurations, it actually performed better on Linux vis Proton than it did running natively on Windows. This is a rarity, as most games run either similarly across Windows and Linux, or with marginally slower performance on Linux, but it serves as a good example of just how impressive a technical feat has been achieved by the people working on Proton.
Fans of the prior game who were hoping to play this new entry on Linux are in luck because it has just had Linux support via Proton fully implemented. Disappointing some players, it was not supported at launch, meaning there was no option to play the PC version on any OS other than Windows, but as of right now it is indeed fully playable on Linux. The reason it was initially not working was due to the DRM implementation included in the game, but fortunately, this has been mitigated with an update to Proton, and now the game is effectively officially supported on Linux.
Expert users can force games which are not officially supported by Proton to run by manually selecting the “allow all games to run under steam proton” option, but there’s a good chance that you’ll encounter bugs, glitches, performance issues and games which are entirely incompatible. This is generally more something that would be done for testing purposes, and a feature that would be used by developers working on Proton, trying to get games running properly.
Doom 64, too
On Proton.db, a site for tracking compatibility for various games on Proton, it is marked as “Gold” level support, which means that it runs perfectly, but may require tweaks on certain hardware/software setups. This is slightly short of the Platinum rating (which would mean “runs perfectly out of the box”), but perhaps with a bit more testing and tweaking, it will be able to achieve that Platinum rating.
Also worth noting, the new release of DOOM 64, the previously console-exclusive title which was included with DOOM Eternal as a preorder bonus, is also rated as Gold level compatibility, so if you bought the main games and got DOOM 64 bundled with it, you are not missing out on that if you play on Linux either.
Even for users who are firmly in the camp of using Windows to game on, Proton is a great initiative. There are some older games that do not run properly on modern versions of Windows. Even though Microsoft put a lot of work into trying to maintain compatibility with legacy software, it’s never 100%, and some of these titles do run properly on Linux via Proton even when they are not playable on Windows 10. Having the ability to bring your library of games to another operating system is a great option, and this effort by Valve and the open-source development community means that many of your games are no longer trapped on Windows. Proton is getting more robust over time, improvements are implemented with consistent updates, and it’s getting closer and closer to 100% compatibility by the day.
Do you do any gaming on Linux? Has the option of playing Steam games on Linux via Proton impacted your gaming habits? Are there any big games that are currently not supported that you’re waiting for? Let us know in the comments.