Desolation Tycoon

The world has ended, but life moves on. Your home is a wasteland scoured by winds blowing in from a caustic sea. Most large mammals are extinct, and insects have filled their roles. You are a merchant traveling this land in search of profit. Each character you play starts with a randomly generated history and traits. And eventually, each character's career will come to an end - whether through successful retirement or tragic death. The game remembers everything you do, and the world is persistent across characters. As a consequence of your actions, civilization will slowly grow and rebuild. Accomplishments accrued across any number of characters will unlock new cities, new crew units, new challenges, and so on. There is no fixed storyline. Instead, you have a setting, a set of gameplay mechanics, and complete freedom to do with that what you will.