Couple thoughts...Good composition and use of stock figures. Neat assortment of vehicles, too.
You might want to be a bit more careful in cleaning up your figures, I still see some big mold lines in places, especially in the hands of the guy with the canteen next to the jeep.
The jeep appears to be at the head of the column...I don't think he'd kick up that much mud onto his own windshield. In any case, he'd surely be running his wipers to be able to see where he's going.
Given the mud you've depicted, the guns/barrels should be covered. Getting all that grime in there could make for a very unpleasant surprise upon firing.
Try to carry the ground work up onto your figures a bit more to make them seem more part of the environment.
Try to get the vehicles, especiallly the tank a bit more into the ground. That much muddiness would leave a very soft surface and you want you stuff to look like its weight is bearing down into the road more.
Please consider these as suggestions for refinement on a very good piece of work.