First thought:
Now THAT is a catchy song!
But other than that, this game really oozes style. Very cool concept.
I was extremely glad when I got that first sloth energy boost, because the slow movement at the start was quite excruciating! I'd probably make that powerup a bit more obvious and a bit earlier on so as to not put the player through too much pain before that relief. It could probably even make a nifty little cut-scene/gag.
Visually, it's got a cool style, but it could use some polish.
I think it's a really awesome concept, and I think if you used this as a base prototype and went to town on polishing up the gameplay and visuals, you'd have a pretty nifty game.