That's a fun concept, but you might want to speed it up a little bit. I stopped at 20 because I got bored, it's way too slow. The ball moves too slowly and the paddles should shrink a bit faster. The change that occurs between 1 and 20 should probably happen between 1 and 5, or 1 and 3 instead.

Edit: oh wait, it's way more fun on Safari. On Firefox it feels slow and slugish, but on Safari it's great!