It was...... ok for a first
What I see as the problem for First time animators that are doing the whole stick figure kick ass thing is this:
1. As in Yours you are using the line tool correct? The problem is the line thickness is set at 1 which makes the stick figures look a little crappy. If you look at the bottom somewhere it has the ability to change the thickness thus makes your stick figure look better.
2. It was very choppy. You NEED to make the moves look more natural and smooth so be careful not to move to much at a time.
3 . Last is this. You nee to use... Better sounds that scream sound is used waaaay to often with a lot of movies. And also the Punch sound was the same for everything that hit.
So do that, look up tutorials for animating, an take a little time on the background i am sure you will make a decent stcik fiure flash.