Quite a nice little dio. Good balance and feel overall. Love the camo job on the M4 and the weathering job on the engine. Is the white representative of snow?
Just some small observations, seeing as you asked:
If you slightly turn the turret on the tank and raise the gun slightly you get a less static looking model.
The figures look a little glossy but that could be flash
The tall clumps of grass look good, but maybe a few smaller clumps would help fill out the scene and look a little more natural. Tall grasses like that go to seed, and smaller clumps would be scattered around. Also grasses like this tend to be tall in the centre but have smaller blades at the outer edges, and these usually fan down.
The depth of the tread marks in the soil behind the tank would indicate wet sloppy ground, so the grasses would probably have more green in them, and the tank itself would probably be set lower in the earth to match. The clumps of snow indictae late thaw so the grasses would have greened up by then.
Grass seed gets blown about by the wind, and usually lodge in depressions or up against something. Given the size of the grass clumps, there would definately be some grass growing around the base of the tree, the trunk and roots forming a natural seed trap, and the rocks.
Deadfall branches and a few leaves under the tree might add some more depth to that item
The spare road wheel still has the retaining pin, plate and nut on it. The pin was usually welded to the hull and you had to undo the nut on its end and take of the rectangular plate to get the wheel off the vehicle. There really should just be the hole in the centre.
Just a few small things. The dio is still great as is, and you should be proud of the result. Thanks for sharing.
Just one more thing, if you can, try and take your pics in natural light (not under direct sunlight, and use a pale blue bedsheet or something pale blue as a back ground. The blue helps difuse colours and will help stop the overall orange tint you got in the pics from the colours of the basework. Blue is a good contrast for most colours, which is why you usually see pics of models in magazines with a blue background.