Okay, I absolutely love this game. Played through to the ending. Unlike some other comments, I didn't find it frustrating at all, because I just saw it as very chill. Some levels took me a lot of attempts, but I just relaxed and found it very satisfying as the topography of the level gradually filled in a bit more with each attempt.
When I go back and replay levels, why do all levels past 23 say "uncleared"? I've cleared all of them.