Joel - Your Concept sketch is really nice. The mood is nicely developed. SO far so Good. I have Two recommendations.
ONE - Try more Variations for the Environment, though Nothing wrong with your present one but try out something else
may be its looks better.
TWO - OK for The main character, i have a humble recommendation. I think so far the character has dead expressionless face, Give him features. Pronounce them more. That will in my opinion give it personality. Something more we can easily relate to. I hope you get what i mean.
Lets see how everything progresses i will stay tuned 
thank you and Best of luck.
Regards