A pretty enjoyable game, albeit extremely difficult. My biggest complaint is the controls and overall game feel. The movement is a little floaty. The jumping could be greatly improved by having it's height based on how long you hold the jump button.
I also saw you make use of particles after hitting an enemy, and those could be used to heighten the game feel (particles on footsteps, and on being hurt) alongside adding sound effects and a little camera shake.
Good work on this one. (also the player sprite is adorable)