got up to 15 - then some blocks felt down and one stacked on it's edge, so it was impossible to put a new block on it properly. physics doesn't always do what you want. But it's a nice little game, if you could make it more appealing, maybe having some cool background instead of a skybox, which you can discover, when going higher and higher =) or maybe some different blocks and a more interesting start area.

keep up the good work!
Scorpion