I agree with the last guy
Far, far too much posing. I know that it's a lot easier and quicker to 'animate' something when it's essentially a montage of stills, but to me it's one corner too many that you've cut. Your characters are already made out of very basic shapes, and they have floating limbs - things which make them a lot less time-consuming to animate. You've also used white slashes on a black screen instead of animating them actually hitting each other.
But you haven't actually animated them, really - just shown them in a variety of still frames, with some slight tweening to give the illusion that they're moving and not posing. As a result, the flow of events is anything but smooth, and what's going on is hard to follow. A pretty lazy attempt overall.