Thanks for the replies !
Yeah, I might need a little bit more contrast, specially when I restrict myself to only tow shades for most of the colours.
For the blond hair / beards, I just didn't bother making other colours, I restricted myself with this to compare the different characters shapes more efficiently. Not everybody is going to be blond :p
I'm also thinking of a way to adjust the hue of the sprites within the engine, to save time and space. No multiple sprites, just multiple colour code.
Note that the "engine" I speak of is actually zero line of code long, so far. I'm that deep in that project.

Tweaked the running animation, legs adjusted to depth and lateral shift. Also added shadow, because why not?

Working on some snowy landscape, makes me realize that character with good looking colours on a green background looks really really dark on a light background...