One-button rhythm game that somehow has a surprising amount of depth. Try the demos and trust me when I say there's more to it than "just count to 7". For a preview: Counting multiple different rhythms at once... varying rhythms... strange songs... and (I should stop here to avoid spoiling the in-game window shenanigans) a window to a whole new world. With your finger you can save the world! Or at least the people in the hospital.
Well, I don't think there's quintuple time in Rhythm Doctoryet (at least as of Act 5 release first minor update?)