Very nice, I can see where you are trying to go with this, but, the ground needs to be broken up with some more grass and shrubs I think, to much of a monotone look if you know what I mean. If this tank is going through that thick of mud, the tracks need to be dirtied up more and some mud on the fenders, road wheels and front/back of tank wouldn't hurt.
In addition, I would dab some mud on the boots and bottom of the coat.
Very nice, just a little more small things could really make this dio come to life.
-Shain