Give clear technical explanation and help
The most frustrating part was that this game AND the instruction seem made for 4+ (don't get me wrong, I like the design!), but it takes a huge IQ to figure out how the stuff exactly works, as the link with reality gets lost fairly quickly. So a tutorial with explanation and examples would be nice. A hinting system highlighting the hard points in each level, or even better, straightforward feedback on the weak points of an attempt would make me love this game, where now I simply gave in after less than 10 levels. A pity for a beautiful game with so many levels, especially since I really like physics games.