So, a few things that stood out was the position of his shield, his anatomy and the coloring. Some of this has been pointed before, such as his face and eyes. I let that be, as I assume that is what you were going for anyway. The things that I changed were mostly color and anatomy, I also warped the shield to make sense.
I pushed his left shoulder back, defined some muscles, such as the serratus, trapezius and latisssimus muscles. Male nipples are often further to the side than the middle. I also warped the pectoralis major a bit, as they aren't usually that boxy. I gave it definition as well, so it wouldn't look too flat and stale. I exposed the clavicle, and defined some muscles on his arm.
Lastly and most importantly, I changed his skin. I get that you were going for a pale viking guy, but the skin color you created simply doesn't exist. The palest of people, have saturated fleshy tones. They stand out more, due to the majority of their skin being pale. Now, I exaggerated his skin to help you understand how skin coloring works. Pale people have more of a pinkish tone rather than orange. Anyhow, I hope this was helpful!
