I finally got it to work. Arrow keys to move, space to attack. This fight is HARD and takes a while at that, so it's a true accomplishment to beat it. I will know how many people beat it from a cloud variable, so go for it!
Jonny Atma AKA Gametal made the remix of "Dirty and Beauty" from Kirby Triple Deluxe, and the rest is straight from Nintendo themselves. No, her laugh is not Sonic.exe, it's Kefka from Final Fantasy 6 or 3 or whatever you want to call it. UPDATE: added automatic "skip cutscene" feature after first attempt. UPDATE: Fixed attacking finally UPDATE: Fixed bug in phase 3 on repeat attempts. (Not that anyone's gotten there) UPDATE: New attacks in phases 1 and 2! More varied attacks in phase 1, several minor bug fixes, and new intro for phase 3. This may be the final update, so enjoy, and thanks for the support!
