Very beautiful pixel art (awesome work on animating the main character), fun gameplay and cool sound effects! I guess making the collisions a bit smaller on the y axis would be good. Otherwise, I enjoyed the experience! 

I thought that this was a fun little platformer. I really do like the low-res pixel art style. It's one of my favorite art styles. 

However, the tiles do have this glitch where black lines appear frequently. I actually ran across this problem for my major indie game I am currently developing. When you make a tileset, you should make your tile textures one pixel bigger in each direction and duplicate the edges of the tiles out, if that makes sense. They would clip to the second edge,instead of clipping to nothing, which makes it less noticeable, if at all. 

Other then that, and the kinda slow attack animation, I liked the game

I FINALLY BEAT IT
Wow, that was such a difficult game to beat!

Just the sheer amount of tiles, animations and the fact that you still had time to create music and sound effects is very impressive! Not to mention the number of levels you have managed to pump out!

I do agree with the things Gunnar Clovis mentioned, so I won't repeat that, but to add to it- I did encounter a tiny glitch after attacking 10-ish times where the character gets stuck in one of its attack frames and is not capable of attacking anymore.

Other than that, it's amazing how you managed to make this feel like a complete game when you were given only 9 hours!

I beat it! Though I was sad when the level just wrapped to an earlier stage.

Really impressive, looks really good, it's really cool you have so much content here.

The controls/physics feel really bad, and the background would frequently glitch out a bit, showing seams. I'd often get stuck on the side of platforms, and a lot of the time the platforming was really frustrating. The level design needs work, you're just asking the player to jump down not knowing where there's spikes and not. It becomes more just trial-and-error, memorizing the stage than any kind of learning or mastery, which isn't very fun. The sword feels really stiff, bad, and awkward. Dying at all feels weird, the animation is so slow and anticlimactic.

The game feel in general has a lot of room for improvement, but again it's so impressive that you have this fully featured and fully functioning of a game with so many levels! Nice job!