This game gets kind of difficult as it goes, as using up the lives means you will return to the first level. Since the gameplay is linear, restarting from the beginning is kind of repetitive. I also encountered a bug that froze the player after respawning. There are also some rooms for improvement, like adding death animations, creating sprites for the UI components.
Overall, the graphics of this game fits pretty well together. The animations and the sprites are pretty cute. I like the sound effects for jumping and attacking that really add some feedback to the player's actions.