I think you can do more with the hands and feet. Give him a third leg on one side that appears and disappears rapidly as it walks, and on the other make the foot huge and flat. Also add a couple edges and delete a few faces on it so it looks like it has a pair of long clawed toes. Take the back and palm of one of the hands and bring it up to where the shoulder is but leave the fingers so that they look really long. Take the other hand and widen the same parts so the whole thing turns into a trapezoid shape. Stretch out one of the arms and yeah, as the others said, mount a second head on it.