Sorry to hear that. Have you made sure your graphics drivers are up to date?
Hmm. That's unfortunate. Older Unreal builds can be tricky some times. The Steam version is slightly newer - it might be worth trying that one.
If you bought Bonbon on here you should be able to access a steam key.
If you got Bonbon for free or in a bundle, itch won't give you a key, but since you're having issues, if you email me at aethericgames at gmail dot com, then I'll reply with a steam key.