!!!
To some degree, I agree with the others, in that a lack of a "quest" format leaves a little to be desired and makes this feel a little more like a demo than a complete game. That said, if you call this a demo, then it would have to be the best flash demo that I've ever head the pleasure of playing. Graphics, music, and gameplay are all superb.
It was difficult to distinguish what stuff actually acted as walls and what was just confounding decoration that could be swum through, and there was an awful lot of confounding decoration. That made it more challenging and actually a bit more fun to explore, but when it came to racing it started to annoy me. If I were very motivated to optimize my racing, I might go from checkpoint to checkpoint slowly and meticulously on a mapping run to figure out the optimal path and memorize it for an actual race. But that seems like more work than I really want to do because I'm lazy.
The acrobatic subgame had to be my favorite. I'm very much looking forward to another William and Sly, and would like to see such acrobatics play a role in it.
Me no likey the quiz tho.