Giten Megami Tensei: Tokyo Mokushiroku

In 199X, Tokyo was destroyed by ICBMs, resulting in a nuclear holocaust. Some people with foresight had built underground shelters and survived the Great Cataclysm, while demons began to rampage on the ground. People in the underground shelters still need to defend against demon invasion, and thus an organization called Devil Busters have formed. Around 20 years passed, and a new generation has grown up in the shelters...