Overall, these are good! I believe the NES limitations on sprites is four+ transparent, so these fit that requirement well.
The one thing i would say needs some improvement would be color choice in general, namely for the wolves(?) six sprites down. IMO, it looks a little off to have such highly contrasting colors in the palette. try changing the yellow-ish sone to more a cool gray. that'll work better with the, what looks like, blue shade around the outside of the form.
