Excellent animation
the Shadow fan in me hated watching him get the beating of his life, but I cannot deny that you put some might excellent effects to work with those sprites, and the close ups were also surprisingly clear... I was quite impressed. A quick run down...
Animation was great... which it was very little in the way of "New" you definitely have taken an over-used medium and refined it. I liked it, I wasn't bored... and it was neither jumpy or rushed. You know how to animate and that much is evident. I'd like to see you do something expanded... a little bit longer... and watch that. I want to see what you do with a prolonged and even fight and how much effort you are willing to put into such an endeavor. If what I have seen here is a measure... you could have Newgrounds gold in the future.
I realize that this was a test, but there was no story... so that did make it kinda seem like: here is Shadow getting the piss kicked out of him. This is payback to all the Shadow lovers out there. I would have liked a small explanation... so that bored me just a little. (you can only watch someone getting trashed for so long without wondering... what the heck? and why for?)
Excellent music choice, btw, and the voice clips were fairly well done... though Sonic sounded like Goku in one section... I don't know if that was intentional or not? I heard a line during the tornado... it wasn't very clear, I could have been hearing things... but if not--you may want to make it just a bit louder.
All in all everything was excellent... very nice test run.