What a cute game!
The music was good on most levels and the graphics were alright. I was particularly satisfied by the smooth controls.
The distinct lack of violence was refreshing, I liked that. If you ever make more of this, keep the violence out, there's quite enough of that on here as is.
As for the difficulty, I passed the game without ever dying even once. I'd say don't add checkpoints, it's not too hard but not too easy either.