See below for the help for your particular computer: Windows The location of your game saves varies based on the operating system you're using. RimWorld saves are made locally (on your computer), so if you ever change computer, make a backup or want to share a save with someone else, you need to know which folder they're in! Simple in principle, but at times seems impossible practice. The end goal is to research technology and develop your colony to a point at which you are able to build a spaceship to escape the planet you crash landed on. There's deadly weather conditions (it's not Earth, after all), fires caused by lightning, enemies named raiders that will storm your town in groups, and that's just to name a few. In order to keep your colony alive, you're going to have to avoid the endless amounts of things on the planet that are a threat to survival. The colony you're tasked with managing has crash landed on a planet in outer space. Technically speaking, RimWorld is a 'Colony Management Simulator' in layman's terms, that means you're tasked with managing a colony.
Although single player, there are multiplayer mods that allow you to play on RimWorld with friends. It's available on Steam for Windows, Linux, and Mac (OS X). RimWorld is a 2D single player game by Ludeon Studios that launched in October 2018.