A difficult game, but the controls are pretty nice once you get hang of it. The checkpoints are pretty lenient as well, though maybe on later stages it's not that lenient.
One thing that I may suggest is a stopwatch. I think this game is one of those games that could benefit from a stopwatch. I can see a huge speedrunning potential here.
A little bit of gentle nudging towards the next goal would be nice, since I had a hard time navigating where to go on certain places.
Overall, a really nice game. Simple mechanics, simple art style, but very satisfying to play once you get hang of it.