Niceeeee. I only took a few stars because no music, a little hard to control I think because the speed changes since the player's diameter changes (did you try it with the speed constant?).
I was thinking of marking down for the Fun because I couldn't beat levels 5, 8, and 10. But that's a me problem. I think your level design was good and the world needs more stealth games (like Splinter Cell).