Although the game would run with the PROTON_USE_WINED3D=1 suggestion posted earlier, this would not render the background correctly, making it difficult to play, and losing a lot of the graphical value of the game.

These three things did the trick for me:

1. Add this to /etc/X11/xorg.conf.d/20-intel.conf:

   Section "Device"
      Identifier  "Intel Graphics"
      Driver      "intel"
      Option      "DRI"         "3"
   EndSection
   

2. Install Vulkan libraries with:

   sudo apt install mesa-vulkan-drivers mesa-vulkan-drivers:i386 vulkan-utils libvulkan1 libvulkan1:i386
   

3. In game properties, force use of Proton 4.11. Proton 5.0 did not work for me (would not even launch).