Overview:

The protagonist (player) pours all his money into a nuclear shelter in preparation for the world’s inevitable collapse.
Everyone ridicules him, calling him crazy.
But the time has truly come.
As the world collapses and people suffer hellishly, the protagonist (player) chuckles alone in the safety and comfort of his shelter, thinking he was right.
Then, a group of young women visit him, asking him to let them in.
“This is getting fun,” you chuckle, slowly opening the shelter’s door.
The player controls the shelter.
Women cannot refuse if the player demands their bodies.
Selling their bodies to someone will also trigger erotic events.
If you fulfill the woman’s demands when having sex with her, her favorability will increase, leading to more playthroughs.