The detail, weathering, and thought you put into it are all excellent! I didn't know, or think about, the backblast (although it drives me crazy when Rambo fires a LAW from the front seat of the helo in Rambo II without cooking the guys in back of him) - what I did wonder, however, was why the Russian soldier is coming up on the position from behind. I'm sure there are lots of scenarios where this would, and did, happen - but by default you'd expect the Neberwerfer to be facing the Russian advance. Despite that, I wouldn't ask you to redesign the base just for that - it's so nicely done I would hate to see it changed. And like I said, I'm sure there were plenty of positions like this that were surrounded and then knocked off piecemeal.
Is that the ESCI 1/35 Nebelwerfer? I have one that I abandoned partway through - if I remember, it was because I was too ham-fisted to be able to deal with the small parts without breaking them..