Oh boy.
All right. Here we go.
Firstly, please add a play button. I left the room, and suddenly music starts playing and other sound effects begin to sound off.
Secondly, like zabutei said, I don't understand why they're fighting, what's going on, who the protagonist and antagonist is. So as far as I can tell, the story needs to be more clearly shown.
Thirdly, the facial expressions are the same the entire time. Even while the gray haired guy is getting kicked into a wall, he's still smiling. I did like the drawings though.
Fourthly, the animation seemed a bit slow. Being a fellow animator, I know how difficult it can be to make a fight scene look good with your characters arms and legs still attached (take madness for example, no arms, or legs) but either way, you're adding in the limbs, so you've gotta make it look good. Take a bit more time to make things look fantastic.
Fifthly (Yeah, I know), try changing camera angles more often. It'll keep the viewer more interested.
Sixthly, please add voices. I can't tell you how old school it is to have text at the bottom of the screen.
Lastly, I don't know how you did that fire thing when the chick was... firing up, but it was great! I'd appreciate it if you let me know how you did it!
So, I know that seemed like a pretty harsh critique but I think that you've got potential. Just spend a bit more time working on each episode and they could be great.