• Go into Desktop Mode
  
• Navigate to this guide
  
• Copy the following line of text to your clipboard:
  
  PROTON_USE_WINED3D11=1 %command%
  
  
• If you're only using the steam deck controls, clicking the left trackpad acts as a right-click, which should give you the "copy" command
  
• Open Steam (still in desktop mode)
  
• Navigate to Thrillville off the rails
  
• Either right-click the game in the list-view and click "Properties" or click the gear icon in the big view and click "Properties"
  
• Paste the command into the game's launch options:
  
  Special thanks to ProtonDB user JRGD who discovered the fix: https://www.protondb.com/app/6080#V5KnmgP0GG

The game will be running now, but certain in-game cutscenes will be replaced with a "test bars" pattern. The intro may play, but the videos that play during levels will not work properly.

In the case of Proton GE the latest isn't always the greatest so it takes some trial and error to find one that works with the game you're trying to use it with. Follow this guide to install custom Proton GE versions and use it to install PROTON-6.21-GE-2, this version seemed to work for me.


Alternate link if the embed doesn't work: https://www.rockpapershotgun.com/how-to-install-proton-ge-on-the-steam-deck

After you've installed this version of proton, go to Thrillville's manage menu/compatability and check "Force the Use of a Specific Steam Play Compatibility tool", and choose PROTON-6.21-GE-2.