Looking pretty good. The grayscale and the lettering effect when you beat a level is a nice touch. I would suggest documenting the controls, though. I eventually figured out that [2nd] is to restart a level.
Though the concept isn't new, it's a good game nonetheless, and very well axecuted. (I stopped playing after level 4 because the difficulty went up and it's rather "late" for me to be awake. Can't think straight.)
If you want something to occupy your time, give this game a try.