RimWorld

The objective of the game is to ensure the survival of a colony of people ("pawns"), fighting against various environmental and internal events through randomly generated events in a customizable world. As the game progresses, events become progressively harder and the player can unlock more advanced technology through research. The game is two-dimensional, viewed from a top down perspective.

In-game events are procedurally generated by a "storyteller" algorithm; game difficulty, event difficulty, and difficulty progression depend on its settings. The storyteller will analyze the player's current situation and choose events based on what it assesses will make the most interesting narrative. The game has three pre-configured storytellers: "Cassandra Classic", who follows traditional storytelling techniques of rising and falling tension; "Phoebe Chillax", who allows for additional downtime between events; and "Randy Random", who forsakes a narrative altogether in favor of randomness and excitement. There are 6 different preset difficulties to choose from, along with a custom difficulty option. These presets influence the severity and frequency of events, as well as the balance of positive and negative events.

The game is set in the distant future, where humans are spread across the universe but cannot travel faster than the speed of light. Planets and star systems develop in isolation from each other, and while some societies advance technologically, others regress due to war or disease. As a result, there is a massive range of technological levels among societies, from Neolithic tribes to reality-transcending machine gods.

RimWorld has multiple starting scenarios to choose from, although the core narrative is largely the same. The player oversees colonists stranded on a procedurally generated planet located in the frontiers of known space, and must form a functioning colony with the survivors. They must contend with both the environment and hostile inhabitants of the planet to survive and eventually escape. As time passes, more characters may join the colony; they are able to be rescued after crash-landing on the player map, wander in, or be captured after a raid.

Tynan Sylvester (born 1986 in Canada), the lead developer for RimWorld, had his first experience with game design by creating custom levels for Unreal Tournament as a middle schooler. In 2008, he joined Irrational Games and helped develop BioShock Infinite for four years before leaving the company in February 2012 to become an independent game developer. As he tried to figure out what sort of game he would develop, Sylvester made a series of prototypes of games resembling Project Zomboid, Smash TV, Football Manager, and Hitman. He settled on the RimWorld concept after a game test with friends one evening, during which two of them became so absorbed that they couldn't bring themselves to leave until 2 AM: "People were falling asleep but they still wanted to play". RimWorld was inspired by Dwarf Fortress and Firefly, and its art style by Prison Architect.

RimWorld was publicly revealed on September 15, 2013. A Kickstarter campaign was launched for RimWorld on October 2, 2013, which earned CA$268,132 in 30 days. The first public alpha build of the game came out on November 4, 2013. From 2013 to 2018, the development team hovered between two and three developers.

RimWorld has received "generally favorable" reviews for Windows according to Metacritic, a review aggregator; the Xbox One version received "universal acclaim". Nomura Hikaru of IGN rated the game 9/10, describing it as "an all-in-one package for management simulation", and writing positively of the way it handled the player failing and its ability to tell a story. Sam Greer of PC Gamer gave a generally positive review, declaring that it was "a rich colony sim" and finding that its mid and late games were entertaining, while disliking the early game. Brendan Caldwell of Rock Paper Shotgun wrote positively of the game, commending its ability to create drama. RimWorld has been favorably compared to other management-survival games, including Dwarf Fortress.

In February 2018, Sylvester announced that RimWorld had sold over a million copies. By August 2020, it was estimated that RimWorld had accumulated well over 100 million dollars in revenue, making it one of the most popular indie games on Steam.