Doomsday Global Flood

The polar ice sheets suddenly collapsed on a large scale, coupled with continuous torrential rains across the entire region, and the massive accumulation of water caused sea levels to rise rapidly: coastal cities were swallowed up by the tide, rivers burst their banks and flooded inland plains, roads and bridges were washed away by floods, tap water and power grids were completely shut down, clean fresh water and storable food were quickly in short supply, and low-lying settlements completely sank to the bottom of the water. The streets and alleys of the city have turned into a vast land, and people can only retreat to high ground and isolated islands on rooftops to survive. All the convenient logistics and water supply infrastructure in the past have been scrapped, and the entire land has been cut and dismantled by flooding floods. Power outages, food shortages, human greed, giant beasts under the sea, and doomsday crises are everywhere. (Pure survival text, no system or abilities)