My Post-Apocalyptic Shelter Levels Up Infinitely!

As disaster was about to strike, a group of survivors transmigrated into a desolated world and were challenged to a game of survival. From terrifying acid rains, to endless natural disasters, the heavens burn while the earth scorches, radiation is rampant, and nobody is spared from the dangers of this hellscape. The only way one survives is by building a shelter and slowly upgrading it in hopes of surviving another day.