-METRO 2033: (since stalkers already mentioned) made by most of the same team as stalker but with an even bleaker take on the setting. Mankind destroyed the world in nuclear fire. To a degree many assume even the afterlife itself was destroyed in the annihilation. Now what human life remains is born of the few people that managed to get into the Russian Metro before the bulkheads sealed. stations became towns. Lines were drawn. Neo Nazis fight Communists for control of the north, the core stations of Polis form the closest thing to a governing body and around that traders keep the more 'rural' towns alive with trade of meat from the animals brought down into the metro that feed on the mushrooms grown as the second biggest export. For most life goes on with brick and iron plated skies and every station adrift in a void with only dark tunnels leading into the abyss between stations to connect anywhere else.
But its not the only life left in the world. The radiation has twisted and mutated all animal life on the surface and sometimes these monstrous creatures delve down into the metro seeking warmth or food. By 2033 something new has appeared. Something that walks on two legs, can talk directly to your mind and turn a man into a cabbage with a thought. Some call them Undead, others call them Homo Novus, humanities replacements and they are starting to get into the dark lines and one by one stations are going dark.
So already its got its hooks as a sci-fi but part of the allure of METRO is that those theories about the afterlife being gone might be true. You live in the metro, you die in the metro. With multiple sections of the game and the novels showing outright supernatural events where ghosts roam the dark tunnels between stations and only wisened guides can escort stationfolk through certain areas because lights and compasses dont work and people swear the shadowy outlines of people can be seem in the dark, reaching after the small hand operated trams that speed through these as fast as possible when urgent needs require passage through them. You want atmosphere then a game mostly set in a run down and haunted metro system after a nuclear war is pretty up there.