Still happens in "Proton: 1738185976 proton-9.0-4d"
Command: PROTON_LOG=1 %command%
Also background music doesn't play, "Helen's Mysterious Castle/helen/Gamedeta/Music/Church.mid" isn't in the start screen for example.
Although sound effects like for confirming options, is fine.
And the save menu has ÿ where empty spaces would be in Windows. Gotta unlock saving first by getting the Longbow inside the cabin.
Compatibility Report
System Information
LOG:
steam-418190.log
Symptoms
Game runs, but when switching to fullscreen mode using the F4 key, the game window disappears.