Global Catastrophe: Only I Have a Shelter

In AD 2111, disaster struck! Numerous collapses have occurred around the world! From the bottomless pit, terrifying alien creatures are pouring out one after another! Meteor impacts, extreme temperature differences, and waves of monsters come one after another! Lin Cheng, who traveled here a year ago, built a shelter in advance and awakened the system three days before the great liquidation. Bite! The level of the shelter has been improved! Get the system reward: superconducting electromagnetic gun! [Ding! A large increase in survival supplies in the shelter was detected, and a system reward was obtained: a space shuttle door! While people were still fighting for a piece of bread, Lin Cheng had already started to help Gatlin clear the nearby alien creatures and plan the underground city...