gives a nice feel

pretty ok :)
what FPS is it in anyway? 40?

This isn't serious

I see you're trying to keep a light atmosphere in the animation, and that's fine, but still, there are many places where you could improve on it.
The title is obviously inadequate, as is the lack of submission icon. Having a user icon of your own wouldn't hurt the overall look of the submission page.
As for the submission itself, try to frame the text in a box at the top or bottom of the screen (keeping it in one place is helpful) and add a button to proceed with the text when done reading. A lot of the text was too fast, which is a common mistake: after working on something long enough, you'll know the lines by heart, but the general audience won't, and will be reading for the first time. I'm sure there are some tutorials here on NG that could help you with that.

not horrible

Good Things:
Smooth animation
a story
backgrounds
Action and sounds

Bad Things:
Sticks
bad colors
not 100% clear on whats happening
no voices
Not blended together right.

Pretty good 4 a 2th one

You should improve those fired bullets, add more details to the background. add a play button and a replay button too. Good luck!

here is my "constructive critism"

the story is good keep it up!!,...and if u have a sequel,please add some sound,and remove the text talk thingy, oh and try to improvise the background with something........i dun know....cool i guess???,...one last thing....don't change the character with something "humanized"...stickman is good enough!!!

6/10 & 3/5 4 u~... =)
(P.S if u cant add some sound its OK....but remove the text talk thingy(or maybe just add some baloon text like a comic book)...)