yaaay, cake! very simple concept, but not too much for a GameJam.
I loved the realistic physics of not being able to accelerate while in the air. but fortunately I could still stop sprinting, otherwise I would not been able to make those tricky jumps in the end. I nearly quit there.
PS: when pressing both arrow keys at the same time and releasing one, the character moves without the walking animation :)

I think this game has some solid potential. Just needs some polish with it's platforming. Getting out of water onto a ledge is a touchy, and the air mobility could use some work. Add on some anti-frustration features likes coyote time and input buffering and you have a solid platformer.