Running thoughts:

• Coyote time would be something to look into for cleaning up the platforming. However, I will say I didn't implement it in mine, so I can completely understand if that was the same
• A few of the initial platforming parts had blind jumps, which aren't ever nice. But also a poor feeling at the very beginning of the game
• However, your small animations are pretty polished and enjoyable to see, such as the vertical lines upon jumping

I reached the final level and failed. I would say that your character and enemy art style are visually easy to understand. However, your level design could use some improvement.  I would say the audio, as someone who doesn't like piano, is very easy to relax to and fades into the background.  With a little improvement in level design, I could see this being a very nice 2d platformer.