Play button in the Steam client is sufficient.I cannot start the game. It crashes on my system. :/

I managed to get it to work by adding "PROTON_USE_WINED3D11=1 %command%" to the launch options. It also worked out of the box with wine 3.19
After Nvidia driver update from 410.78 to 415.18 the game fails to launch with popup message "Fatal error in gc, GetThreadContext failed". Downgrade to 410.78 solves the problem.
Wired Xbox 360 controllers close to not usable. Steam detects them but the game doesn't take standard controller layout. An okay'ish fix is to map keyboard input to the controller, but this makes local co-op a hassle though.
Beyond the controller issue and the Nvidia 415.18 driver error - the game has been running fine from the get-go on Proton 3.16-4 Beta.
The nVidia GetThreadContext issue has been reported fixed with the 415.18.04 Vulkan dev driver.
Play button in the Steam client is sufficient.I consider that fully working controllers is essential for a party game like this before it is whitelisted. When played at a friends place it worked flawlessly to use a mix of wired Xbox 360 and wireless PS4 controllers for five people on a Windows 10 system. This shouldn't be whitelisted before the controller issues are solved.
Adding "PROTON_USE_WINED3D11=1 %command%" to the launchoptions let me start the game too.
Thank you https://github.com/ValveSoftware/Proton/issues/1304#issuecomment-435016318 @pboiski
GPU: GTX 940MX
Driver/LLVM version: NVIDIA 430.26
Distro version: Ubuntu 18.04.1 LTS
Proton version: 4.2-6 Beta
crash while playing.tar.gz
crash without start parameter workaround.tar.gz