Hello @stuglaser, your system information tells us you do not have Vulkan drivers installed for your video chipset. Please run sudo apt install mesa-vulkan-drivers mesa-vulkan-drivers:i386 and retest.
Installed Vulkan, and enabled DRI 3, and now it seems to work! Thank you!
proton 5.0-5x1 2020-04
Compatibility Report
System Information
I confirm:
Steam log report: steam-210970.log
Symptoms
I click "Play" in steam, get the "Preparing to launch the Witness" dialog, which eventually disappears, and then...nothing. The game does not start. The "Stop" button reverts back to "Play".
Reproduction
Click "Play"
(I did not find any relevant PR's or issues)
Thanks!