Rimworld is a huge timesink with a million dofferent things to do and two million workshop mods on top of that. Build a colony on some backwater planet, defend your people, keep them healthy, and MAYBE you’ll manage to get a ship off of the planet if the hostile elements don’t get you first.
There are some RNG events that decide what happens to your colony for better or worse. Maybe you will find a drop pod filled with food in during a harsh winter, or maybe a swarm of rabid squirrels will break down your doors and leave no survivors. Your colonists all have their own wants and needs too. They can fall in love, have affairs, mentally break down and go on a murder spree, or just snap and wander off into the wastes. It can be a struggle to keep the colony happy AND secure, but sometimes you gotta do what you gotta do… Even if that means sending a highly skilled pyromaniac sharpshooter on a suicide mission so he will stop burning all of your crop fields down.
There are so many things you can screw around with and build, plus with countless mods there really are no limits to what you can do. A great value for the asking price and a fantastic prisoner organ harvest simulator, totally recommended.