Alright Grazr, as you have helped me with my yammering on steam, I'll try to help you.
Picture #1: The ground looks quite bland. Perhaps add some grass sprites or some more rocks, or add some different alpha blending to break up the mass of monotone dirt in the centre. I like the style of the building on the left. It kinda reminds me of dustbowl for some reason. The ladder and Tire are nice touches.
Picture #2: Ironically, the roof here is quite bland too. Perhaps you should refer to your roofing tutorial? XD Again, the floor is quite bland, and you appear to have added a door just to break the monotone of the wall. Unfortunately, you have not included any sort of detail room to show the purpose of the door; unless the door leads to the exterior wall? I kinda expected to see some conduits or something from the floodlights from outside to connect to and was dissapointed when there was not.
Picture #3: You said to me in PM that the concrete block was used as either: A road divider, or a thign of defence. In this picture, the concrete block seems to be doing neither of these, as it is not placed by a road and can not easily be used to fire from behind (unless there is a not visible structure). The visible building in the foreground has a nice use of overlays, however the conveyor seems to dissapear to thin air (unless you plan to implement this in the skybox). The skybox itself is nice; it won't take away player attention because it is subtle. I like how you changed the room with the window near A into an extension of the adjacent building.
Picture #4: The wall here is quite tiled. I understand that you wouldn't want a relateively insignificant wall to capture player attention, but it just looks an eye-sore. Perhaps make it similar to the curvy silo building in picture #5? There isn't much more to critisize here other than the tiled floorboards.
Picture #5. I don't get what the strange 'oil rig' structure in this picture is. The boxy one. It's also pretty strange: 2 thin cables holding up a giant metal conveyor. that structure doesn't look like it would withstand the forces of gravity. Its almost as bad as thinking oil can form under rivers in mountains. B is looking nice, as is the fence you mentioned in you blog.
Thats all from me folks.