Short simple and straight to the point. I like that. The checkpoints although not visible, are appreciated to not make the player retry difficult sections of the platformer. It is strange to me how hard the boss was even though it was very easy to predict the attacks. I wanted to quit playing when dying to the boss over and over. I think it would be helpful to know how much health the boss has left to encourage the player to keep trying. The art has nice style, and it is consistent throughout the game. I would have preferred if the music did not restart after each death.
Overall, a clean game. Not sure if there was a way to exit the Controls window. I had to restart the game to get past it.