Space and all the keys on the home row (except for g; I tried to get g to replace space, but it didn't work).
I added a point system! You gain a point for every arrow you hit, and lose one for every arrow you miss. I don't have anything yet for when you press an arrow that isn't supposed to be played then. Also, yeah, clicking random keys actually still gets you a positive score in the second half of the song; Rush E is just like that, I guess.
