What's probably bothering me the most is the black lines defining spaces inside the wolfs rather than just color values/shades of color, but that might just be me.
I'd only put a black outline around the very outside, at most, if at all. --And Instead of a black outline, I'd rather prefer a shade of a color that's near-by.
Some animations look ok, but 2 frames is hardly enough to the mind/eye to look anything but choppy. Also the timing could be different on different frames to make it ease in and out.
The dithering doesn't look so hot either, I'd personally just add a few more values and use AA.
Some of the lines look off, either looking rushed or out of shape with the volumes of the body.
The colors don't seem to ramp in or out of saturation. Just looking, they all look like the same sat.
Also, any lighting going on is hardly noticeable
No one enjoys my edits, so I'll leave this up to you or someone else.
Enlarged wolf sprite from final fantasy 6, notice how much detail has been put in using so few pixels.
Also notice there are just values inside the body rather than pure-black lines: