sorry to put a hic...
Well it's "great" without being the best work on newgrounds(much better than other work tough), for a trailer i think it's way too long, and doesn't match with the movie you are promoting(you are just showing the character, you need to put sequence of your movie for a trailer...this was more a preview to show how the quality will be).
You got some good graphic, so waiting for the movie to put a real mark.
ps: I like the way you drawed the moon and the sun :) oh bye the way : Why knukles is helped by tails? He can "fly" too , no? :)