Apocalypse - Infinite Shelter Upgrade System

Solar flares erupt, massive meteorites descend, and a great catastrophe is imminent, reminiscent of the Ice Age and the extinction of dinosaurs. Sam crosses over to this world, immediately confronting the apocalypse! Fortunately, he obtains the Infinite Shelter Upgrade System, activating his exclusive shelter system that can be upgraded infinitely! Iron door → Sandwiched door → Alloy gate → Laser passage... Crossbow port → Small-caliber machine gun → Large-caliber machine gun → Thunderstorm machine gun → Laser cannon... Radiation-resistant suit → Exoskeleton armor → Mechanical armor → Small-scale mech → Giant mech... Crossbow manufacturing station → Firearms workstation → Arsenal...