RimWorld

In-game events are procedurally generated by an AI storyteller, which is central to gameplay; game difficulty, event difficulty and difficulty progression depend on its settings.[11] The AI 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 preconfigured AI storytellers, "Cassandra Classic", who follows traditional storytelling techniques of rising and falling tension, "Phoebe Chillax", a more laid-back storyteller, and "Randy Random", who forsakes narrative altogether in favor of randomness and excitement.[12] There are 6 different preset difficulties to choose from along with a custom difficulty option. These influence the severity and frequency of events as well as the good, neutral, and bad balance of events.[12][13] Events can range from simple occurrences such as wild animals wandering into the map or spacecraft debris crash landing to catastrophic long-lasting events such as cold snaps or volcanic winters.

The game has two save-modes. Commitment mode acts as Rimworld's permadeath mode, disabling manual saving, and Reload anytime mode allows the player to save and load freely, giving the player a chance to undo an event.[14]

The characters' mental stability is represented by a mood meter, affected by basic or complex needs, personality traits, and character backstories. Characters require food, rest and shelter but will also request a place to sit while eating, well-made and undamaged clothes, or enough time for recreation like stargazing, cloud watching or playing chess.[15] If needs are left unmet, characters may undergo "mental breaks" such as going into a daze or even going berserk and attacking other characters.[16]

With the release of Alpha 13 on April 6, 2016, a new social aspect to the game was introduced. Characters were given the ability to have social relationships with each other, and an opinion system was introduced. These relationships can benefit or detract from the needs and joys of a character, and poor social relationships may result in fights.[17]

Animals in the game may be domesticated or tamed, and can form relationships with human characters, but they cannot be controlled directly by the player. Certain animals may be taught commands, which vary from simply obeying its master to defending them if attacked to occasionally carrying and storing items.[18]

Players can research new technologies by constructing research stations. Players may harness electricity, which unlocks a plethora of machines and increases the colony's efficiency, but they are forced to find ways to generate electricity, including wind turbines, solar panels, or geothermal power stations. Players can also unlock other advancements like medicine, advanced weaponry, or drugs.[19]

Players may be forced into several combative events. For example, during a pirate attack, the player will have to defend the colony by either drafting the characters or by building defensive mechanisms around the colony.[20] Such defensive measures may include traps and automated turrets. A key mechanic in combat is cover. Ducking behind cover, such as trees, walls or sandbags, gives characters a much lower chance of being hit by projectiles during firefights.[21]

Characters in the game need constant nourishment. One of the challenges of a larger colony is finding a way to feed all the colonists. Players may combine hunting, farming, animal husbandry, and trading to meet the colonist's needs. Animals can be lured and tamed with food, but there is a small chance the animal will attack the tamer instead. Upon being tamed, domestic animals can reproduce.[22]

On December 20, 2016, Alpha version 16 "Wanderlust" was released. Many new features were added regarding the world map, including: a spherical world map, time-zones, factions now starting with many bases, the ability to travel across the whole world map, the ability to set up multiple colonies, world generation, and customizable world map parameters. It is possible for players to attack other bases and plunder resources from them, angering the attacked faction in the process.[23]

Players are able to install modifications (known as "mods") distributed via the Steam Workshop, the game's official forums, or other distribution sites. The game is known for its active modding community, regularly publishing mods from simple quality of life upgrades to complete gameplay overhauls.[6]

In 2016 RimWorld was voted Indie DB's "indie of the year".[34] In 2018 Rimworld was voted Steam's Top User-Rated Game,[35] from all categories. The game was nominated in 2019 for the category of "Strategy/Simulation Game of the Year" at the 22nd D.I.C.E. Awards.[36][37] In 2020, RimWorld was ranked the best management game on the PC in Rock Paper Shotgun.[38]

In February 2018, it was announced by Sylvester that RimWorld had sold over a million copies.[39] 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.[40]