I like how in depth you got into the whole animation. There were plenty of nice angles, good shadows, and nice gun shots. The art design of the arm gun and the rifles was pretty good too.

My only concern is the actual stickfigure movement. Correct me if I'm wrong, but are all your motions tweens? It looks like it. If so, using tweens to animate will give you perfect results by having nicely drawn sticks, but I think that using the line and brush tool will give you a better feel for animating.

If animating with tweens is your style, then that's by all means great! But tweens lack the ability to give a more realistic feel of movement than the line or brush tool. I know that it may be much more difficult using line or brush, but it is for all of us. I recommend trying to use brush or line to animate, even if the results come out terrible. Even if they do, you or anyone who practices over time will get better.

Your art, present skill of tweens and 3D perception are amazing, and I feel you can do the same with brush or line. Keep animating!