Hey aregon good progress. Glad you decided to work on the whole form.
Here are a couple things though:
The fingers are very long and spindly, and kind of sharp. Perhaps make them stumpier and straighter.
The lines on the arms are pretty good, but I would make a few alterations. First, at the elbow, the skin comes in towards the bone and connects. In yours, the forearm muscle starts before the elbow. You should move that lower lump out more towards the hand, like this:
Next, there is an interesting proportion in people. They are almost exactly as tall as their arm span is wide. Trust me, some of my friends are identical twins, and I made one bend over and extend his arms from the others foot to his head, it fit perfectly. So in your piece, here are your dimensions:
As you can see, his feet would have to be massive to fit the proportion. The problem really is his arm span is too wide. Look at the Vitruvian man again, and see that from the top of the head to the middle waist line, that is half his height. So I noted the number of pixels from the top of his head to his waist line, and double that should be the arm span, and total height. So thats about 162 pixels.
Lastly, pillow shading, ahh! It isn't that bad because you are using the shadows to suggest form, but it is pillow shading nonetheless. If light was directly hitting the abs though, it would not light them like that. It would penetrate the indented parts more. Consider putting the light above him, like you did on the pecs and armpits. Those seem to be shaded correctly, but the arms are not, and neither are the abs or neck.
Though, I do really like your chainmail texture. It is readable and well executed.
