There are several noticeable problems with this flash that I could go on and on about but I'll keep it short and simple so as not to ramble on.
The fight was terribly scripted and lacked any fluid or smooth motion. That can easily be fixed by animating proper sequences in Flash and adding in tweens. The lack of proper camera movement is also an issue and I would suggest downloading a V-Cam and learning how it works. It would also be a good idea to use hit sparks after every successful strike and shake the screen to show the impact of the moves.
The text is also a problem as it looks as if you added it in using Windows Movie Maker. Add the text in Flash instead as it gives you more options to play around with.
Sound effects are also a factor that should be added for obvious reasons but I'm sure you figured that out yourself.
Aside from that, its nice to see people still interested in sprite movies as they were insanely popular 6-7 years ago.
Good luck.