Hello @TheSandBoxMKG, Proton uses DXVK to translate D3D11 to Vulkan and you need the mesa-vulkan-drivers and mesa-vulkan-drivers:i386 package to support that on Intel graphics. However, Mesa 13.0.6 is well below the requirements for Proton and not worth troubleshooting until you update to something newer. You may have some luck with adding PROTON_USE_WINED3D=1 %command% to the game's launch options.
Closing due to min-spec requirements.
PROTON_USE_WINED3D=1x1 2019-01PROTON_USE_WINED3D=1 %command%x1 2019-01
System Information: Gist
OS: Debian 9 Stretch
DE: Xfce 4.12
GPU: Intel HD Graphics 620
So... I was trying to test Yu-Gi-Oh! Duel Links when I met the same error message in found previously on another game:
So I tested to run the game via terminal, not from the Steam client and went futher than running from the Steam client (It crashed in a black screen but following this I was able to get futher until the "Couldn't connect to the Steam server." message appeared).
In conclusion, I think Proton has some problems running Unity games from the Steam client in some linux configurations.
This is the log when is run from the Steam client:
steam-601510.log
I don't know how to make log from when the game is run directly from the terminal, but here's at leaqst the output it does in the terminal:
Gist