Im running Linux (More specifically Arch Linux with kernel 5.7.12-arch1-1 and wine 5.14-staging) and i did not uncheck full screen i had the same problem in both the native Linux build and windows build via wine
Viewing post in Pugonalysis jam comments
Really sorry to hear that! We will try to fix the build in the post-jam version, but I really do not have any idea what happened! When I test the linux build, it works fine if I don't uncheck the fullscreen box, and the windowss build with wine works completely fine, even not in fullscreen. I need to state again the fact that Unity does not like linux. Maybe try the post-jam version after the jam.