If this is not yet finished, I have one last...
...suggestion.
From the end of the trailer, I am guessing that what I saw was Hyper Sonic. Just about every time I see Hyper Sonic in some way, shape, or form in a flash movie, he is either solid white, solid blue, or glowing colors, but the wrong colors and in the wrong sequence.
What I hope to see in the final flash is that Hyper Sonic (if he is indeed in it) is glowing the way he SHOULD be glowing (or, if not that way, since he appears to be light blue, glowing various magnitudes of light blue).
I am not sure if you know this, but viewers, like myself, often look for detail. Yes, your preview is good, and the movie, obviously, will be better, but I suggest making sure that at the end, it is not ruined by a solid white or solid light blue Hyper Sonic. Showing Hyper Sonic, at the end, in his alternating color state and keeping that up for the rest of the flash movie shows that the makers are really paying attention to detail, and the overall experience will be much more entertaining and fun-filled.
I cannot wait to see the final produce.