Great stuff.
I think it's awesome how no one is talking, personally. No characters talked in the Genesis games (reasons are obvious), but because of that, I've always felt that no one should be talking in anything else. The voice actors, and most voice acting, just ruin the series. Nothing can ever be right, so why do it anyways?
Let the action and music tell the story like it's always been. On your next few, I think you should work a little bit more on the fighting. Make them faster, and more intense. They seemed kinda slow -- I wasn't sold by the fighting. Look closer at the actual Sonic anime -- the movie itself would be good aside from Sonic X, and maybe even fighting series like Dragon Ball Z, and study how fast-paced, varied, and alive the fighting is.
You have too much potential. Keep trying, and keep making improvements. :)