I'm running Ubuntu 20.04, and I am experiencing issues that make the game nearly unplayable. Depending on where objects are on the screen I see large purple box around objects that is kind of like a purple filter that doesn't effect the UI. I have seen these boxes on the first stage whenever my mouse moves to the right side of the screen, or when I pass to the right side of the first character you meet. There are also these big blue boxes that either cover, or replace the sprite, and it also obstructs other objects. I also have a slow, 200 dollar PC, so maybe that contributes to the issue? Anyways, I know you didn't test for Linux, and it might not be your first priority, but it is a pretty big bug. Oh, I also just realized you could add images, so here's one. Where I am, everything is purple.