Really neat idea. First game so far that I felt compelled to play more of just for the fun of the challenge. Once you internalize the pattern of the level it's really satisfying to try to play to the rhythm and particularly try to thwart the moves that will careen you off the edge.
This is a good example of the spirit. It gets its core concept across and after playing it I had all sorts of ideas on how it could be expanded. Nice work!