cool sprite and cool idea
first thing that caught my eye was whats going on with the rear hand.
at first seemed like he was loading the gun or something.
now i see what its doing but still think u should change it so it doesn't look like its involved with the gun.
front leg animation needs smoothing its only 2 frames.
have u tried passing a gentle 1 pixel waving motion across the whole body?
by that i mean front section waves up, then hips, then legs as front drops down and so forth.
this would be in addition to the existing animations of each part.
just in idea.