Man - we have had a slew of first time diorama people posting - It is GREAT. Love seeing new talent coming in and posting!!!
Your 1/2 track dio is very good. I like the action and movement. The layout is good and I like the angles you have in it. The 1/2 track is well built and finished very well.
Here are few thoughts I share with all first timers. A few things I always run through my head during design and placement are 1. How did each piece get to where it is, did the figure run, jump, drive, etc. I play through and I actually 'do the movement' with the kit. This ensure I don't have a tree in a vehicles path or that the path is wide enough etc. 2. Does it make logical sence for the 'whatever' to be where it is? Would a figure run across an open field? Would a machine gunner be prone with no cover? 3. What's the next slice of time. If you could progress the dio. another moment in time where would the momentum of the story take the action. 4. Does the progression work?
If I may offer some points to consider when you work on your next diorama. Consider filling in the gap at the corner where the two rock walls come together. If the conditions are muddy, don't forget the figures boots and then inside the AFV. They could use a spot of mud/dirt.
Very nice diorama. Keep up the good work and by all means don't take the things I have pointed out as negative. You should see my first diorama

Yous is good.