Nice simple game!
I sometimes randomly couldn't jump though and I found out that you can move both the camera and player by using the arrow keys, but you only move the player by using A and D. This allowed me to walk off screen and change where I could see my player on screen. Maybe next time try and write a camera-follow script and experiment with that instead of just moving the camera with the arrowkeys, since you can also hump a wall to make the camera move, but not the player or you can make the player slide down a little to move the player forward, but not the camera.
The game can be quite difficult at some times, but I like a challenge :). Nice, cute and simple art. It's a good game for your first jam!