Far to short
The main problem I saw with this, was that it tried to explain a new plot, new characters and a new setting with just a few words, in under 15 seconds. Then expected us to understand what it meant.
It was then followed by random violence, the most simplistic pull-off on Newgrounds. It would of been alot better if you threw away the 15 second attempt of a plot and just added some more killing, or god forbit, put more effort into your animation.
The way it cut straight into the fight scene, as if it almost expected us to understand what was going on was somewhat weird. It was basically taking the random stick killer, giving it a quick outline and throwing in a plot which took 30 seconds or less to invent.
Along with the thrown in storyline, the visuals were par at best. I saw alot of motion tweening, hardly any frame by frame and you severly missed out on the fine detail (he pulled the shotgun chamber, only his arm moved?). The animation was smooth, but when there is no visual or perceptive backup from the drawings or style of animation, well it doesn't work in the first place.
The characters were copy paste material, no uniqueness in any of them. No symbolic meaning, which once again made the plot look like a last minute attempt.
The backgrounds, paid off. Some decent shading effects and nice foreground to look at, probably your best peice.
The music, was very nice. Though, if you add any fast music to a kill em all it tends to go well, so no points there. The sound effects were in reptition and no special loop, dubs or editing to initiate the spacial differences between them.
Overall, it looked like the cross between Xiao Xiao and Madness... but without the talent. To much tweening, it all looked the same and once again, the plot looked like it was invented after the flash was made... not a good point.
I think if you honestly put some effort into your work, you could pull off something alot more enjoyable than this.