Larger image looks nice -- you might want to emphasize the clown-shine on his red nose in the larger image, and for the smaller animation make him look at his opponents a bit more while he's punching (just seems to be punching at the air while looking at a butterfly or the pretty clouds at the moment.) You could make him fit the drunken bum stereotype a bit more by making him appear to be falling over after he punches if you like. Would add an interesting gameplay element imo.
As far as the jacket goes, imagine it as the single piece of thin mass that it is, making it appear to follow after the initial action. Not enough change in the silhouette and shape of the jacket nearest his stomach/hip area. Possibly make it flap after the punch happens if you don't want to go overboard with the drunken-stumble-punch animation idea.
Finally, I'm not too sure about the collar flaps -- they move downward for no reason during the punch. If anything they should stay where they were while the head moves down, perhaps distending slightly with the downward movement of the head, and popping forward only after the punch is pulled back.
The biggest issue overall, however, is that his torso and/or shoulders don't move at all. At least try to shift his shoulder/chest area forward when he ducks to punch to get more 'change' in your animation.
