Looked good, with nice calming music and sound effects and a pleasant game overall. Nice job.

Fantastic concept, and you implemented it brilliantly. 
Although I'm rooting for Shadow the Hedgehog

The controls are really smooth, and I like the look.

Controls feel quite natural, great job on that! :D

The gameplay felt somewhat lacking unfortunately. I wish that different states would have more impact on the game. At first, I thought I could swim if I were in the rolled state; this could have been used to reach an island and collect a ring. Additionally, climbing up and then releasing could roll the player down the hill to break a crate at the base, revealing another ring etc.