You should add a menu screen with Level Select, Credits, Maybe a link to your homepage (or wherever), plus some spiffed up graphics. Also, different difficulties would be nice. You could give people a time limit in the harder ones, plus less lives. Also, a total play counter would be nice, just for the purpose of high scores.
Great start, however the fact that it goes back a level when you lose should be optional. Maybe make different difficulties which include: Less Shots, Loss of Levels, Smaller Ball, etc. Also an upgrade in graphics would be sweet. 3/5 for a good beginning.