Clown Robot Doctor Apocalypse

From the introduction: A fallout shelter megaplex dreamland hides under the jungle. Vines and foliage cover a pristine metal door that requires a key card for entrance. Within is an elevator tube. To get to the city, the visitor must pass through a dense tangle of stairs, catwalks, tubes, conveyors, ladders, pipes, wires, ducts, girders, and utility chambers.