A Good Idea...
Hmm, well, might I suggest improving the collision detection a bit? It seems as though you can only "die" when hit in the center.
Other than that piece of advice, the game was...enough to distract me from other things. There really isn't a point, and with no sound effects or music, it was a lonely game, if that makes sense.
All in all, the idea was good, but it needs to be polished more.