I'm just kinda doing whatever comes to mind now so here's a rhythm game concept. How to play: Just hover your cursor over the little creatures when they're no longer transparent to pop them and get points!
Green: When they uncover their eyes, put your cursor over them to pop them Pink: Just touch them with your cursor Red: Avoid having your cursor touch this one, as you'll lose points! Yellow: Same as Green, but happens multiple times with a shorter time window.