I really loved the concept you have aproach for the theme and i absolute loved the menus with all the customization options.
I would suggest improve the gravity or the physics you apply to the player because you can pass levels by floating around by spamming 'W' and 'I' without even using plattaforms. I would aslo like to add that there's a minor bugs with the music volume, but no biggie.
I fell that if you improve this pyshics and movement issues is a game with great potential
Keep it up!