The arm is pillow-shaded, which is a problem right now. Also, I'm having trouble figuring out your light source, mainly because there's no cast shadows. Like, for example, shouldn't the axe cast a shadow on the arm?
Thanks for the advice!
The light source is on his front left side, from above. So I tried to make everything brighter on his left side (our right). I think you'll see that if you look closer, but I suppose there are areas where I've made mistakes which are throwing you off. Perhaps the metal?
Since I'm not working from a reference with great resemblance, and since I'm working with a somewhat limited palette, I admit I'm having trouble showing the light source, while also showing depth and illustrating the shape of the armour. Especially for the metal, because I want to do shiny, polished metal, instead of dull, brushed metal. And figuring out the way the light reflects is tricky.
The arm has the opposite problem, because sharp highlights makes it look like it's covered with metal instead of skin, and with 4 colours I found it hard to create depth while indicating the light source clearly. Now that you mention it, the lower arm and upper arm have conflicting light sources.
The axe should cast a shadow on the arm and/or hand. That didn't even occur to me before. Though I can't really imagine where it would fall and what it would look like - I don't have an eye for that stuff yet. I suppose his helmet should also cast a bigger shadow around his neck.
As usual, I have overextended myself in terms of difficulty level, so any kind of suggestions would be helpful.