You can always try running the Windows version in Proton if you have issues. I use Linux Mint myself and the Linux version runs fine for me though. Always remember to set executable permission if you haven't done so already.
(me being dumdum)
I've turned on that permission and the game is running smooth now! The only design issues I have is that there's a softlock after entering the prince's jail and in one of dark places, there's a certain invisible spot, which isn't explosive that instantly kills Purupuru. And as well those pink/purple jelly things that also kill her if not properly set up.
Either way, this game has fun designs and a decent gameplay! Good luck with the rest of the development.