Nice, nice, nice
Looks very good.
About picture 4:
I can't see the barrel of the top-gunners machine-gun.
And there is seems to be light in the upper air-intake of the engine, just an edge, but that shouldn't be possible because there should be shadow.
Another thing, the head of the Spitfire pilot is against the cushion of the seat. There is talked about that, so is that an old screenshot?