They look alive.
When the "Lines" are a little bit "fater" and smoother they look more alive if you know what I mean.
I really like how their spikes moved like thet when the wind was blowing. The battle is really good, one of the best I've ever seen. And of coure, you picked the right music for the flash, it really fits and it is one of the best things with the movie. You watch an awsome flash movie and at the same time you hear awsome "kick ass" music.
And the style looks like a mixed version of Sonic X and the old school Sonic, and that's cool.
I give you ten! You're awsome.