Well, I must say this is quite fantastic so I'll go ahead and start with the critique of this. :3
Vision: Well, Eggman's voice actor seems to deliver quite a fantastic performance and he is dead-on with impersonating Mike Pollock. The sound design and background and the overall atmosphere give this feeling of preparation for what could well be an outstanding battle or the destruction of Sonic.
Originality: I can't really say much for Originality since I haven't seen the full film yet but so far, it comes off as an original project to me.
Technique: Well, animation-wise, this is simply fantastic and you can be the effort put into this teaser.
Impact: This has impacted me quite well. It makes me anticipate the release of this fan film all the better.
To quote a great mad scientist, "This should be fun! Ho! Ho ho ho ho ho ho!"