Pretty good
but it has definite glitches. For a demo its pretty fun, but i could only get to the second level because when i died the ball would fire in a random direction and id perpetually lose lives. that happened twice. also sometimes the paddle absorbs the ball and fires it downward, and on top of that the "walls" don't do anything.
other than that good concept and it was an interesting twist to put a music question in between levels, but there should be some way to tell if you get it right or not. i liked it, but it was rather glitchy.