Nice layout and theme for the diorama Model Maniac, I see credit has been given to Art Instructor as I understand you promote others work as well. Three items that I would do different are as follows:
#1 The airbrushed camo should have more defined shapes vrs random blotches. The soft edges bleed into each other more than they should.
#2 The road wheels look like they need some of the hull colors as it appears like they belong on a straight desert yellow vehicle.
#3 More restraint on the blackened muzzle brake, black in the bore faded to grey is more realistic.
Take this as constructive as I am not trying to 'rivet count' the other wise great build. The placement of figures and painting of them is excellent, very realistic and convincing.