Really nice stuff here. : - )
Just one crit i thought of about your last picture with the wolf.
I really like the colours and the way you handled the depth in the right side of the picture, but it seems kind of pointless. Whats going on in that portion?
About the silouhetted figure. Maybe you should consider not going so dark in that portion of the picture, as light would come into the tunnel, bounce of the walls and then at the figure. Im not saying to detail the interior of the silo, but just rais ethe value of that general portion of the picture.
Also, think of your composition perhaps. The right side is as of now sort of pointless and empty. It makes the image seem a bit off balance (imo of course). Personally, i would just crop it so that the wolf and the figure are somewhat on the "thirds" of the picture.