Hello Emms,
Base-comment:
for the base, quite good shape and absolutely believable. Maybe the colours are "very bright" and not tolerated in this common CMON taste, but what the heck!. For beeing more believed as jungle bases, some surrounding vegetation might be successful applied. I think grass won't do, so some grainy darkgreen sponge remains as moss does it better? Don't really know.
Barbarian-comment:
I think the barbarians-left-hand axe is nearly completed, so it's only the discussion what to do with the scratches. Imho its only the ratio of white and black, what it doesn't make it feel right, either some more grey inner, or reducing the white to the same ratio of the black.
From the B's back I assume the blades are finished and great ( You've to teach me the howto). The golden poles are awesome! The fleshy parts of B's back are very convincing. The only lack imho is the nearmost same tone of flesh parts and leather parts. Makes it difficult to separate them. Maybe some weathering of the leather could separate them optically?
I have no receipt to do armour plates of such small size, but imho on arms and hips they should have the same reflection effect as the blades, but I think you wait to the last (I would).
Only one minor critic: The face hasn't the same broad richness of skintone as the back, also the B's right upper (inner) elbow, which has to obey the rules of lightreflection. To have the look and feel of obsidian, some dilluted shade of bright(blueish) green (e.g. jade green) from top to down and after that a tip of white to the upmost point for pretence of reflected light will improve the small plates. The belt buckle has a large area, so imho it must obey the same reflection as the blades and armour!
Armour-Leather, the ocre-whiteish tone is imho the original one, the only difference to the rackhams method is that you didn't applied a black (or dark brown) undercoat, so it didn't have the border to separated colours for the eyes (blacklinening). There is no failure in the colour. But I wouldn't change this on this one. (Sorry for some misspellings, but i've to hurry)
Be courageous!