Close But No Cigar
I have to say, for the first 10 levels or so the game is pretty enjoyable. However, I found myself getting bored after the 10th level or so. This was a real original game and rather addictive for the most part. Perhaps, if you could add some more innovative things after the first 10 levels or so to really challenge a player, the game could definitely improve.
Two major complaints though, the graphics are pretty low quality for such a simple game play, try making it 3-D or adding some style. As a whole the graphics were decent though. Also, what was up with that strange sound effect that sounded like a muffled machine gun or a poor man with indigestion? Was that supposed to be the stretching of the tree? I'd advise finding a different sounds, that effect is just ill fitted for the game.