This game is charming in theory, but I found it quite gruelingly difficult, for various reasons.
The player movement is very hectic and feels extremely out of control. The jump is always the same height instead of cutting out when z is released, and the player just moves too fast for how small screens are, especially since there's no acceleration/deceleration. Less instant screen transitions would also help in not dying as often.
Checkpoints are placed far too infrequently, heck, I'd just save on every room like celeste at this point. The hitboxes of spikes could also be a lot more generous.
Enough about that, the art is super simplistic but it works, the music is good on its own, though it did get to my nerves hearing the same tune over and over again due to repeated dying.
It's a good game in theory, just far too finicky and difficult for me.
Good job!