Awesome! I had been working on a similar project couldn't figure out the snow on the trees for the life of me! It's great to see how you approached it. The work look great! Thanks for sharing your process.
I believe author would be surprised that it's not american, but soviet bunker :)
Better Level Design Through Human Survival Instincts (Christopher Totten) 2/6
In the second part of the talk Christopher Totten discusses different kinds of spaces in game level design, such as open space, intimate space and narrow space.