Does using fullscreen count as window manipulation? I wanna know for sure before I start doing any runs
Nope. I more or less copied that rule from another flash game on this site. Because sometimes it is possible to have menu windows glitch (depending on the flash game) and can still be clicked on during gameplay, which can let you skip or access things you normally shouldn't be able to. I don't think it ever really happens on this game but I still have it there just in case.
Recently it has come to our attention that Ruffle has some inconsistencies when compared to Flashpoint and authentic Flash Player, such as slightly faster loading times (around 2 frames), and also some bugs that are exclusive to Ruffle, such as the text in some menus in Sift Heads World being messed