Well I'm going to have to be completely honest
Overall it did not meet my expectations of what I had for this movie. I'll tell you why before you completely take this is a annoying criticism. The number one reason is that based on the teaser you released in 2006 I was really anticipating this flash and it had been so long since any mention of this ever being released and after seeing this out in the portal I got over excited. Then once I finished watching it I didn't meet up to the expectations I had for it. I actually liked the teaser more then this animation itself. A lot of the problem was the music choice and the ENTIRE lack of sound effects for the flash. You can get away with no sound fx in a teaser/trailer but on the finished product it would be nice to have seen a little more effort put into the sound rather then stop dead. The overall quality was a mixed bag. Some areas in the flash have really nice designed backgrounds and great character designs and others will be simple quickly put together vector graphics. The 3D mixing was a nice touch at parts but it also didn't mix well with other parts. It is really hard to say what exactly was wrong with it but it all just came down to minor details that I mentioned before so thats why I didn't rate this low. If there is anything to take out of this review is that you should try to keep a higher level of consistency between scenes, add more SOUND, work on your frame by frame, and try and finish your projects sooner the teasing us for 4 Years.
Overall this will be one of the top sonic videos on newgrounds but I think sonic unleashed may be just ahead of you.