Not bad, but has two fatal flaws.
This flash is actually pretty good. The animation looks kind of low-budget and the colors are kinky, but the progamming and concept are pretty good. Unfortunately, there are two problems which prevent me from giving a higher score.
First up is that the framerate is far, far too slow. 12fps is no way to make a game. For a rhythm-based game, 30fps is the minimum. Keystrokes register slower, the game feels laggy and unresponsive; the controls may not feel bad to you, but they do to me.
Second is that it's way too hard to see the arrows coming down. Semitransparent arrows may look nifty, but they are achingly hard to see and slow the framerate even more than necessary. Solid arrows are much better. I am a skilled rhythm game player, but how can I do the exercises when I can't see the steps?
Try re-uploading the game with this fixed. It's only a matter of changing a few animations and typing in a couple numbers. Until then, you get a 6 out of 10 from me.
-CKY