I played this a few times and it was fun. I couldn't pass it on normal :P
Graphics are basic, but nice, the do the trick. It would be neat to see even a little basic transparent picture in the background, something like DDR.
Sound, I loved it! Probably the reason I attempted to do better each time. I really liked it.
No violence. :p Interactivity is nice. No humor either. Overall, I gave it a 7. It would be neat if you could add some neat lighting effects to the arrows. Even if you don't put an image behind the rising arrows, maybe just brighten it up a little bit. It's a little dark. Not bad though!
Again, really nice! Now I'm going to go try the others you've made :D