Update: There's a hotfix out. It has some media foundation fixes to install properly.
There's no need to wait for Valve and CodeWeavers to update Proton for Steam Play, if you're willing to do a little bit of extra work with a custom build like Proton GE.
Proton GE is one of the unofficial builds of Proton briefly talked about in a previous article, with it just recently getting a rather big update.
Proton-4.15-GE-1 was released a few hours ago updating it to the recently released Wine 4.15. Additionally, it adds in Wine's Vkd3d for running Direct3D 12 games through Vulkan, which you can turn on using "PROTON_USE_VKD3D=1 %command%" as a launch option. There's also an update to D9VK which is on by default, use "PROTON_NO_D9VK=1 %command%" as a launch option to turn it off. On top of that there's also various gamepad updates, fsync was updated and a bunch of Media Foundation work went into it too.
It might sound a little scary using a custom build of Proton for Steam Play but installation is easy though. Close Steam, download the Proton-4.15-GE-1.tar.gz file and place the extracted contents into:
For the newer Linux gamer: a folder with a dot at the start is hidden. Press CTRL + H to toggle hidden files and folders on/off.
When you re-open Steam, it will then show up as an option to force onto a game. Do so by right clicking the game in your Steam library, go to Properties and then this is at the bottom:
Easy as that.
See the full release notes and download here.
What's the benefit over using the Valve provided official Proton? Custom builds might come with fixes you need right away. Say a game is updated and breaks with the official Proton in Steam Play. You might wait weeks or a month but a custom build like Proton GE could come a lot sooner. It's possible in future, that some custom builds might even do things Valve won't or can't officially. It's just another option to get your games running directly in the Steam client on Linux.
Hat tip to Bogan.