Rules of the End of the World: Others Are Trying to Survive but I Am Stuck in a Bug

"Gray Eclipse" breaks out simultaneously around the world - seven cracks appear in the sky, and gray matter pours down from the cracks. Humans exposed to gray erosion mutate into "eclipse bodies" (zombie) within 72 hours. But gray erosion is no random disaster. There is a system of rules behind it - like "game terms" formulated by some kind of higher-dimensional being. The rules are not subject to human will. If you violate them, you will die, but if you use them, you will live. The apocalypse is not a natural disaster, but a game with rules - a man who died according to the rules in his previous life is reborn and is stuck in a bug to survive.