Hey Decroded.
This is a cool little versatile sprite, so I did a quick edit.
The biggest issue here: this sprite puts too much priority on the outlines.
It looks/reads better to focus on the shading. (I.E. the helmet feather here)
Took some colors out (extra grey hanging around some parts of the sprite's outline? took this out) and redid the values, then messed with the hues.
When shading the metal, I was thinking in planes instead of spheres, keeping the highlights small, so it looks a bit less pillowshaded.
Moved the arm up to an active stance, which usually works for player sprites in action platformers like I see this being used in.
Added more contrast to the proportions.
Newer version has more contrast than the older version, which is better IMO, but it's still pretty even.
Try making parts a different size/shape from eachother.
Look out, editing this post soon to put out an edit of the anim.
Busier nowadays w/ work etc. but I'll be coming back to this place.
EDIT: Here it is, watch those subpixels go.
Still rough, not really exaggerated, but implements some crucial stuff like follow-thru.
Bonus thing:
Hope that gives you ideas.