Hello @VancouverJohn, this game is rendering with OpenGL and in general no OpenGL application should cause the system-wide issues, which hints that this is a video driver issue. Are there any hints in dmesg that go along with this?
I found the following logs in journalctl which correspond to the crash of X.
I had this same issue on Ubuntu 19.04 with the nvidia-driver-418 package, but not with nvidia-driver-390.
Hello @VancouverJohn, noted at https://github.com/ValveSoftware/Proton/issues/204#issuecomment-616830044, this game was recently removed from the whitelist, and we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/204#issuecomment-616831409.
Compatibility Report
System Information
I confirm:
steam-590380.log
Symptoms
After a few moments of gameplay, the game crashes and takes down the entire X server.
Reproduction