Difficult but fun!
I really liked your approach to the theme. I have followed a similar but not so similar approach!
The main thing that I think you should focus on is the player movement. It did not feel precise, and the game did not recognize many of my key presses. You can look up for the terms "coyote time" and "jump buffering" to create better polished platformer games in the future!
Other than that, I can see that you can used certain post-processing elements to give the game a good look, excellent! Another things I would suggest visual-wise would be to add a shade to the player character and jump particles.
Other than that, making so that respawning is quicker actually would keep the player in the game for longer. I think you can work on this idea, polish it a bit more, and learn lots of things for your future projects!
Great entry, well done!