Looks good, Stephen. If I were to make a suggestion for composition (not that I'm King of Comp, by any means), it would be:
I'd lose the wall, and border the intended side with some rubble, with a large pile at the corner (forward the tank). Then, have the tank mounting the sidewalk to take that turn... might bring focus to the turn he's about to make with the angle, and draw the eye around the corner, from left to right.
Does this make sense? Anyways, it was my first instinct when looking over the pics. Looks like it's gonna be a great dio when you're done. Can't wait for the finished product.
Steve