It's incredible how satisfying this game is despite how all you're doing is touching to contract some doodads and releasing to release them. Through this simple action and a simple physics system the game create a variety of simple set ups where you can look at the mechanisms at play, figure out what you need to do with them and then apply finesse. Despite the simplicity of this, it always feels good to nail the timing in each level whether by skill or by luck. It's very rewarding idle fun.