Cool!
For your first flash project, that was pretty nice! Though, like others have said; you should make more use of the big space you have given yourself by producing more of an environment, adding more background and foreground details.
The sound could have been better as the special moves didn't have any sound effects. The punching and blocking effects were nicely used but try to find something to use for when your characters are jumping.
Near the end, it seemed you got a bit lazy, especially when Ryu took Ken and Chun Li away from the scene. It was done way too hastilly.
There was a good use of music here, it fitted well apart from when you used the FFX theme tune. It either didn't fit the mood or maybe it was down to the fact that you just slapped it in there without fading it in or anything.
You need to work on your characters' dialogue as it was mostly very cliché and sometimes reeked of old Hollywood cheese. And try to break the habit of using speech bubbles. A traditional SF dialogue bar with perhaps the characters' portraits alongside as they speak would fit in very well.
The fighting was choreographed extremely well. A nice touch was when it went into a second of slow motion as they were dodging. Paying homage to SF vs MK 2, no doubt :-).
To summarise, the biggest flaw in this movie was sound and some of the dialogue. I hope my critique has given you some insight as to were and how to improve!
Keep it up and don't stop practicing!