Yattaaa! <just beat it>
Brilliant idea, couple of points
1. The blocks seem to drop at random locations, could you tweak it so that they are more likely to fall on stacks of fewer blocks, this would prevent the li'l guy getting stuck between high/low stacks. Would prob require further playtesting to get the balance right. Also,if you do this, then you can keep the blocks dropping indeffinitely, meaning you can do a survive-for-as-long-as-you-can mode.
2. Transparency is rather confusing. I can only sugest a diferent viewing angle (tilt up), or perhaps a view rotation.
Anyway, great great game, hope you keep making them