Looks like the fresh Back 4 Blood Beta is working on Linux with Proton GE

Back 4 Blood is releasing in October from Turtle Rock Studios (original developer on Left 4 Dead) and they now have an Open Beta that anyone can try out and it appears to work with Proton GE.

It's notable because it uses Easy Anti-Cheat, and you get the EAC loading screen when you load up the game. Usually, games with EAC don't work with Proton on Linux and just block it entirely. We know that Valve has been working with the likes of Easy Anti-Cheat and BattlEye ready for the Steam Deck release but it's not entirely clear how (or even if?) it's working right now.

So if you've been eagerly awaiting it, now might be your chance to actually try it out properly before the full release. On Linux you will need the community-built Proton GE, since Valve's official Proton gets stuck on the loading screen. All game modes appear to work just fine.

How to install Proton GE on Linux to try it? With the latest version here's what to do:

1. Download the Proton-6.14-GE-2.tar.gz file from the release notes.
2. If this folder does not exist, create it: ~/.steam/root/compatibilitytools.d/
3. Extract the archive downloaded in Step 1, and place the contents into the above directory.
4. Restart Steam if it's open which refreshes the Steam Play list for Proton-6.14-GE-2 to show up.
5. Right click on your game, go to Properties, Compatibility and ensure the box is ticked named "Force the use of a specific Steam Play compatibility tool" then select it from the dropdown box that appears.

With my own testing I have come across three main issues:

1. Stuttering. Like a lot of Windows games run through Proton, it needs to build up a shader cache. It's far from ideal when you first start playing with it stuttering all over the place. Once it's built up, it seems performance is much better. Hopefully Valve will build up a cache for people to download in Steam like other games.
2. In-game chat doesn't work, it just seems to disconnect repeatedly.
3. It really doesn't like MangoHud. Something about to just makes it freeze up repeatedly. Tried through many runs, with the only difference being MangoHud and it just causes weird freezing behaviour every time it's on.

The Open Beta on Steam lasts until August 16 at 12:00 PDT / 19:00 UTC.