Game loads up to the title screen and main menu perfectly fine, but crashes as soon as you try to start a new game with a vertex shader error. Game dev is also aware of the issue and is looking into a way of fixing it if possible, if not, releasing a version without the shaders causing crashes on proton. Game seems to work if you use protontricks to install d3dcompiler_43 and d3dx9_43 or using Proton GE which has the fixes by default. steam-658150.log
Start the game up, go through the menu and try and start a new game, you won't get into the overworld before it dies.
Hello @waspennator, these look like some lines of interest in your log:
FATAL ERROR in Vertex Shader compilation
ShaderName: shWater
memory:67:25: E5005: Function "transpose" is not defined.
at gml_Object_oOverworldWaterSprite_Draw_0
Related: https://bugs.winehq.org/show_bug.cgi?id=54126
It seems to be a similar issue going on with Carrie's Order up, The Joylancer: Legendary Motor Knight, and Bete Grise from dread x collection 3 and probably others.