Not Bad :D
You seem to have put in a lot of effort into this. I liked the whole madness violence feel. The sound effects were good, and the storyline was easy to follow.
Some things to look out for:
-Try increasing the FPS so things run a little quicker because the whole floating bike thing would seem better with a quicker exit
- Perhaps a sound track? some music may have jumped up the tension in it.
- Maybe you could record some vocals for the next one. Give it a better atmosphere and may get more people to acknowledge your flash work.
Otherwise I think this was really good and you deserve a pat on the back! :D