This is kind of amazing.

I'm assuming this was done with heavy use of masking, possibly airbrush, and maybe other painting media? It "feels" like a collage, where every subject is just its own painting kind of composited into the whole. But that gives us completely subjective lighting to work with, which throws our senses for a loop. Just like how old computer graphics are collages of other discrete artworks, again, with no effort wasted on coherent lighting or shadows.