Very fun concept for a puzzle game! Physics manipulation is a great point to start with when it comes to game design, seeing as you can mix and match a lot of attributes to manipulate. Which you succeeded with!
It's mostly a bit hard for me to have the muscle memory to make my plans work out. But oh, so rewarding when you succeed! Puzzle 3 took quite a while for me to understand, but then I got it. I had to give up at puzzle 5 though, as it demanded a bit too much from me.