Nice idea for a game, it looks pretty cool too! (I did a similar look for my game, but I think yours came out a lot better.)
There's a little room for polish: A next shape HUD would be great (some versions of Tetris have a little picture in the corner that tells you what's next). Also, it would really help the game-feel if there was some more feedback on failure (screen shake, explosion, etc.). Right now, it doesn't feel like I crash, it just feels like I stop.
This is a great idea and you should polish it up a bit to make a great little game.