Kewl
This game is great, physics are awesome (how realistic is the gravity here, and even with the blocks that are 5 times heavier?). The levels are designed so that multiple solutions are possible and that in some levels, the most obvious constructions wouldn't be possible and that using the gravity actually IS the key there.
Big ups on this one.
One note though, the platforms that flip over seem to flip over a bit too easy in my opinion, but that's just me, it's possible that other people would disagree with me here :)