My Doomsday Shelter Unlimited Upgrades

When Chen Yang woke up, he traveled across the parallel world of Blue Star.
In the year 2022 of this world, the arrival of the Mayan civilization was postponed by ten years, and a burst of meteorites completely changed the appearance of Blue Star.
Volcanic eruptions, acid rain crises, super earthquakes, prehistoric tsunamis, alien viruses, mutated creatures, doomsday robbers...
In desperation, Chen Yang awakened the doomsday survival system.
Pick up stones, roll leaves, grow fruits, and build your own super invincible shelter.
Shelter upgrade?Unlimited liters!
【Wooden door】→【Stone door】→【Iron door】→【Alloy door】
【Stone Axe】→【Iron Axe】→【Silver Axe】→【Force Axe】
【Hand generator】→【Hydraulic generator】→【Diesel generator】→【Nuclear generator】
Material synthesis?Whatever you want!
【Stone】2+【Wood】1=【Stone Axe】
【Plant Fiber】100+【Leather】5+【Steel Spring Coil】15=【Simmons Mattress】
[Black Silk] 1+[Clothing] 1=[? ? ? 】
When others are still worrying about a piece of bread, Chen Yang has already eaten Buddha Jumping Over the Wall.
While others were still fighting for a bottle of water, Chen Yang had already swam into the private swimming pool.
While others were still fighting monsters to save a bullet, Chen Yang had already made Gatling for all beings!
......
Suddenly one day, Chen Yang discovered a strange thing!
"Eh? My family, why are there supermarkets in no man's land?"
Jiang Yanbing was speechless: "Isn't this the supermarket you opened?"
"oh oh......"