Entertaining if I do say so.
Even though I haven't seen the original flashes; that will not affect my overall critique.
Animation: You did a great job on the backgrounds, weapons, and some clever usage of gradients. However, the first time we see the characters, they look like a step up from the sticks that were used through out the rest of the movie. Not to mention that that very first part could have been better animated. Now, I don't have a problem with stickmen as long as the movie is good, but I would like to see something like this with fully-drawn characters like the ones used in the preloader animation. In addition, cut down on the blur effects (the more that they are used, the more they make older computers lag).
Sound: You have a nice collection of sound effects, and the music you chose was sufficient, but I think you should get some music from the Audio Portal next time. (Try Xarnor, Xenogenocide, and Nemesis Theory's Show No Tears)
Content: I really dig the fights, but they could have been more creative in terms of attacks, angles, and what not. However, I still do see much potential from you in terms of direction. The story, while not bad in premise, is pretty trite and I think you could look to other flash series for inspiration. (Examples: Keegan's Truck Chronicles Ep. 1 or the Dual Arms series.)
What I do like:
-Solid direction and choreography
-Above-average art and animation
-Interesting plot premise
-Good sound selection
-Not very original
-Could have used more fitting music
Overall: Here's your eight out of ten, and I look forward to you improving.