This looks kinda bland, I not sure why but I'll give it a try. The expression looks serious but not very serious, kinda like "How stupid are you" but the background and battle scars say a more "The world is bloody ending and I hate you with a burning passion of a million suns" which makes it lack 'weight' (It doesn't feel serious). I think you could improve this with a more detailed facial expression, things you good do include, larger mouth, stress/stretch marks, smaller pupils, etc (I'm not good with facial expressions, sorry). Another thing that could be improved is the shading. Some highlights on the face could help especially considering how everything else has highlights. Finally the shading on the chest plate could be better, for example the left piece has shading to the right while the lighting is coming from the right, other parts of the chest plate have little shading mostly around the outlines, this makes the detail look painted on. Just be more careful with the shading and that should be better. I hope i haven't offended you with this, I just saw you work on Project Comment.