It started out fine, but as you progress, I feel that it begins to rely too heavily on trial and error to the point where it becomes less fun. It could use a good checkpoint system similar to what you might find in classic NES titles.
Never felt that way about the game myself. I wouldn't change a single thing about the design really. I feel it's one of the indie games which most perfectly captured exactly what I loved about action games like this in the past. It was never frustrating, always fun, the controls are perfect, the move list and level design is spot on. The checkpoints are just generous enough without feeling watered down, and the challenge presented is very well balanced.
If you start to feel that the game relies more on trial and error as you play, I think that's a good sign that you have not been learning more about the game mechanics as you play through the game. As the levels progress, the challenge is ramped up to expect that you have been learning how to react to certain challenges instead of just barely winging it. That might be why.
There are a lot of mechanics in the game which you must discover and learn for yourself by reflecting on what options you have with the limited move set, and how to expand that into creative ways of mastering a given challenge in the game. If you're not playing with that mindset, then it can be frustrating, but the game is designed for people who enjoy stuff like that.