It may have been better to hard-code the camera's y position, just following the camera on the x (sort of like the first super mario bros), but great presentation. You have no idea how much a cute aesthetic and some nice royalty free music adds to the experience.
Oh, and you probably know this, but the collision mechanics are a little sticky when you run into a wall. That's a hard thing to fix though, so I wouldn't hold it against you.