I understand brushes aren't the key to painting. My question is more: Is there any standard brushes in making concept art that are simply "industry standard" because they are known for speed and efficiency?
There is no such thing called industrial standard brush setting, and not all games concept artists paint with great speed and efficiency, when you are not inspired, you paint slow, when you do research for reference you paint slow. When you struggle with structures and details, you paint slow.
I like this version! Placing the aircraft near the top left emphasizes the slight translucency. As always, the details of light and shadow are what make your work strong and interesting to look at. Very ominous silhouettes.
I read somewhere that the screenwriters for the sequel to Terminator Salvation were thinking about setting it in ruined London, they should get you to do some concept art. This is nice, the sunken boat makes me remember HMS Thunderchild from War of the Worlds.