I can definitely see the levels feeling unfair/annoying, but that's by design -- the game is meant to be rage inducing. It was just a fun project I've made over a Friday so it's not too polished.
And I agree, there isn't much of a learning curve, all the 4 levels the game offers are designed to be roughly the same in difficulty, so the player just gets thrown in without really being taught any game mechanics which isn't great.
Appreciate the feedback & thanks for checking the game out!