Not bad at all for your first game! You've got a working game loop in there. :)
In terms of gameplay maybe the most important criticism I have is that often during jumps I wasn't able to see where I'm supposed to land — a little vertical camera adjustment would've done the trick to offset the jump (or perhaps to completely fix its vertical position).
Nice character design with the expressive faces! Keep it up, hopefully you'll join many more jams in the future :)