I really liked the sprite work and animations. They were really cute. The sounds and music were really nice as well. I like the track used in the tutorial section.
As for gameplay, the charged jump and ground-pound add an interesting twist on what would be otherwise a pretty straightforward 2D platformer had a conventional jump been used. The ground-pound was a really satisfying move to use and also had some pretty cute animations. Also the use of the loop theme was a clever way to get multiple uses out of the same level.
Very nice job!