Just excellent. Addictive, beautiful, funky. Excellent graphics, sweet squash-n-stretch animations, wild music. This feels studio quality and I'm flabbergasted that you knocked it out in a week.
I encountered a bug around worlds 2-3 where I couldn't get the star for a level unless it was several seconds lower than posted on the map screen. (I'm so sorry, I wasn't taking notes at the time and I don't remember which levels.) But, I was able to finish in the end!