ReROLL isn't like most survival games. For one, it uses drones -- the machines map out the games' world using real-world map data. Which is to say, the open world you'll be exploring in-game is some of the terrain you'll find in the real world.
Beyond that, the weather and temperature are pulled from the real world too - so if its snowing in Toronto in real life, it'll be snowing in Toronto in the game, too. It doesn't sound like society will match ours, though -- that's why you have to scavenge, craft and survive. Also, there are mutants for some reason. Hey, it's a (PC) video game. Naturally, there will be other humans you have to watch out for too -- and like other survival games, it may just happen that other survivors are the thing you have to fear the most.
The game is being developed by ex-Ubisoft developers who have worked on games like Assassin's Creed and Far Cry. The game won't start out having the entire planet, since mapping it all out takes time -- but this ensures that the developers will be able to give players a steady stream of new locales/content.