The apocalypse + traveling between two worlds
The protagonist obtains a trial-version System that lets him travel between the modern world and the post-apocalyptic world.
He must survive in the apocalypse and establish his own base to earn the System's approval and unlock all its features.
The apocalypse is brimming with wealth, beckoning the protagonist, but endless dangers come with it.
Is a world without order or morality heaven or hell?
