Very cool game, looking forward how you expand onto the game.
As Aniraster mentioned, moving the camera up and down would be nice and being stopped by the landing animations is a bit clunky.
There is no coyote time, which isn't really bad, but people will probably think they aren't jumping when they should since people are used to being able to jump a with coyote time.
I'll also mention it is really hard finding all the energy orbs, last time I played I got to 1.98, but could never find the last orb, it might be nice for a small hum from the orbs to be able to find them all (either constant when you are with in a range, or only when you hold a button.)
The clothing is organized based on when you pick up each item, it would look better if it organized as you got it (so for example jester stuff would always be at the end, and no matter how you pick up the hair styles they would be in order by number.)
For expanding on the idea:
More hair colors would be cool.
A dive that lets you fall faster but go further would help vertical movement, since you don't really go faster at all vertically as you gain more energy, and it feels slow by the end.
Having different ways to move, for example some wingless race that uses energy to jump (Kind of like jump king) could be fun, but not something to focus on since it could be feature creep.
Bug:
As you can see in the video (near the end), if you spam space a bit you can fall much slower, and if you can spam it like crazy (I used a script) you can even get infinite flight as you have a small chance to jump when you press space in mid-air.