In my opinion to have music play during gameplay you need to make sure it's a really good non-annoying loop or else you're better off having nothing because it hurts the polish. Also holy exposition dump grandpa ice cube lol. Level win screen and having to go back to main menu needs polish. I actually liked level 3's music a lot better.
Nice platforming mechanics, double jumping, dashing, crouching. Double jump bug definitely makes level 3 a little hard. What makes it easy is the dash bug?, you can spam dash, assuming that's not intended?