Lovely art style! The character really pops. There's a bit of jitter in the background, and there's a chunk in the middle of the map that feels a bit empty, but otherwise the aesthetic is gorgeous.
The movement is a bit weird, as after a jump, the character still travels in the direction even after the key is no longer pressed, which makes controlling her mid-air a bit floaty. The combat against the regular enemies felt nice enough, except the torpedo guys in that tunnel where you couldn't really go anywhere to avoid their projectiles.
The boss himself was a bit underwhelming, his moveset was a bit murky to discern and he does little enough damage that spamming him with attack is more worth than trying to be fancy. The HUD is also a bit aesthetically mismatched from the rest of the game, especially the boss healthbar.
That aside though, lovely project, definitely has the potential to shine!