This game is amazing. Music is perfect, pixelated graphics and effects are flawless, and characters are cute - all of them, flaming skulls included.
I would call this a true masterpiece, although a short one, but there is still room for improvement (I know it is almost 4 years old, but nonetheless...):
Receeding after damage to have more time to react against next obstacles is a nice touch, but sometimes it backfires - making the girl get damaged a second time by obstacles that are too close. This could infuriate a few players after happening a few times, especially if they are going for the hardest medal. Increasing the current invincibity window by 1 second - allowing her to jump during this last second - would be enough.
That obviously isn't enough to even consider pulling any stars from my review. Well done.