Add "undo" and possibly "redo" actions to make it possible to correct "mistakes" when moving the ball too fast...
I think you are right about the undo feature making the game easier. It was a good decision not to include it. Thanks for responding.
I thought about implementing an undo feature (I think an early internal version even had one). But then I thought that this would make the game "too easy". With a reset-function only, you really have to solve the game perfectly in order to get all stars - which makes the game a bit more challenging.