• Name of the game with compatibility issues: Spelunky
• Steam AppID of the game: 239350

System Information

• GPU: Ryzen 5 5600G integrated graphics
• Driver/LLVM version: 22.1.3-1
• Kernel version: 5.18.12
• Proton version: 3.16-9, 7.0-3 and Experimental tested

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

Symptoms

Spelunky has a mechanic known as bomb cascading where placing paste bombs with the appropriate timing will make the bombs drop straight down, allowing the player to quickly dig holes in the terrain. This mechanic is not working in Linux, I tried 3 different Proton versions just in case but the issue actually isn't a Proton issue itself, this is something that happened in Windows too, but only in 64 bit editions of Windows 8 and older, it is completely fixed in Windows 10.

Upwards cascading (fast placed pasteless bombs) also doesn't work.

Changing the game's proton config to use Windows 10 might fix the issue? Or perhaps 32 bit prefixes, I tried tweaking with winecfg to get it working but it only broke the game.

Reproduction

1. Acquire paste and have around 4 to 5 bombs
2. Find a large vertical chunk of terrain where you can place bombs from the top
3. Place the bombs with a timing that allows all 4 or 5 bombs to be placed while allowing the player to leave, too fast will cause the bombs to explode in the air.
4. Watch the bombs all explode at once in the first explosion or cascade into only two explosions, sometimes three explosions but the explosion usually moves to the side.

Here's a video that shows it, there's also a clip at the end of how it's supposed to work, again, this was also an issue on Windows that only needed to set compatilibity mode in versions other than 10.