Thanks a million, guys! I've tried to study your posts and find a good way forward.
@fskn: He's supposed to have a short sleeve, exposing his underarm and hand. Thanks for helping me improve the shading. I ended up changing the position of his arm but yours looked much better.
@SeinRuhe: I think it's time to quit working as a chef, it's clearly getting in the way of your pixel art.
- I see what you're saying about the feminine posture. His elbows were a bit tucked while his hands were extended to the side, so he ended up looking a bit like MuuMuu. However, I don't want him to hold the sword quite the way you put it, because I want to show off the shape as a single edged sword (in case Netflix calls)
- I understand that polished metal is essentially a curved mirror, I just haven't put in the hours yet to make my brain capable of simulating it. However, I'm spending more time learning about the fundamentals so I will invest some time today to see that video and practice the concepts. Maybe I'll realize my own mistakes after. Why did I waste so much time not studying art theory when I was younger?
Below is my new edit. I think the issue with the helmet is that I really like the kind of V-shape it has when seen from the front. The reference is not simply a bulbous sphere with holes in, it's actually a medieval helmet that looks really sci-fi in its design. Reminds me of Bubblegum Crisis and Robocop, really. And it's not simply a sphere with a vertical edge either. Maybe it's too difficult to convey in 10x10 pixels.

Anyway, I've tried to study your edits and incorporate as much goodness as I could. I think it's moving along nicely although I still can't wrap my monkey brain around metal reflections and I'm not sure about the sword / sword arm.

EDIT: And now I see that the curvature of his shin is wrong. Fuck.