Global Cataclysm: Shelter Unlimited Upgrades

A sudden global catastrophe swept across the world. It is not a zombie siege or an alien invasion, but a sudden disorder of the earth's magnetic field, which has triggered unprecedented extreme climate changes: melting glaciers, rising sea levels, volcanic eruptions, frequent earthquakes, and a mysterious substance called "grey fog" that envelopes the world, swallowing life and corroding buildings. Human civilization collapsed in just a few days, and the survivors struggled in despair.