I think the collisions are a bit weird (there is also no transparency in the sprites) and sometimes you can't jump even though you're not falling (if you go to an edge).
I feel like there could be more use cases for the jump boost as that seemed to be the most fun mechanic in the game.
Perhaps when swapping a character point an arrow to where the other character is, or simply add a minimap highlighting the characters.
Although you do need both (I think), I do feel like most of the time I used one character only.
Regardless, it was a nice short, not too hard game to play. Congrats!