Well...
It looks really nice, but that's about it. The biggest flaw is obviously the unbeatable AI. Like many other reviews say, you could improve that by making the ball faster. Also, a few subtle sounds or a little bit of gentle watery music would really add to the game (with an option to turn off the music)... and a pause button... Oh yeah, and a main menu. Even if there is nothing to do but play the game, you still need a main menu with a play button. It is a MUST.