First of all put a frame counter in, to make it easier for people to reference the frames which need work. Also, the reason the mov format (or other quicktime compatible files) are preferable is that people will need to be able to step through and examine your work frame by frame. Quicktime is generally the most popular player for this…
As for the animation itself, at this stage you should be blocking - so use constant interpolation between keyframes. You want to define the actions clearly before considering breakdowns - Interpolation should be applied only when you are ready to start polishing, using it any sooner will simply confuse things.
As for the animation itself, the weight of the character does not appear to have been considered. Throughout the standing motion the centre of gravity is not where it should be, which makes the character appear weightless. The shifting of weight during the throw also needs to be emphasised. Initial focus should be on correcting the weight problems, and defining the key poses and establishing your lines of action.
Biggest thing - keep it old-school. CG animation might be a fancy version of stop-motion, but all the old 2D fundamentals still apply.
Hope this helps.