Rimworld By Ludeon Studios

When asked about his inspirations, RimWorld creator Tynan Sylvester is quick to point fingers: “Dwarf Fortress, with some space-western Firefly flavor layered on top,” he says. “I'm endlessly fascinated by the combinatorial depth of the stories generated by Dwarf Fortress. Despite being intimidated by the challenge, I've wanted to make a game that can generate these kinds of stories for a long time.”

RimWorld Oct 17, 2018 A sci-fi colony sim driven by an intelligent AI storyteller. Generates stories by simulating psychology, ecology, gunplay, melee combat, climate, biomes, diplomacy, interpersonal relationships, art, medicine, trade, and more. ↑ 3.0 3.1 3.2 RimWorld:: RimWorld 1.0 released - Steam Community - last accessed on 2018-10-18 ↑ Verified by User:Expack3 on 2018-11-25 ↑ Fix: New Colony button not working in Linux - Ludeon Forums.

Sylvester believes the intimidation he felt as a designer can be seen from the player’s perspective as well. “I think there’s a huge population of people who are interested in story-generation games like Dwarf Fortress, but have found them too intimidating to actually play,” he says. “These players want creative, story-oriented play that still has drama and struggle and loss. Those are the people who like RimWorld the most.”

Indeed, an elaborate story generator is at the heart of the RimWorld. Sylvester points to titles like Dwarf Fortress, The Sims, and even more ostensibly competitive games like Left 4 Dead or StarCraft II as being largely about story generation. “What interested me was taking that idea and focusing on it in a very deliberate way,” he says. “It's not about the victory at the end, but about the entire journey of promise and heartbreak, hope and loss. Maybe your story will be a triumph, maybe a comedy, and maybe a tragedy. As long as it makes you feel something, it works.” For Sylvester, it's a broader and richer way of thinking about how games can affect us, instead of always simply focusing on triumph as the primary emotional goal.

Perhaps unsurprisingly, building a system that responds convincingly to player choice has been no easy task. “[Developing] AI is brutal in this kind of game, because everything can change at any moment,” says Sylvester, who presents the example of a colonist finding a path through some rooms to get some food. A hundred things can happen to invalidate this: The room can fill with fire, or the food can be eaten by one of the game’s roaming muffalo [see sidebar], or the room it's in can be designated as a prison. The player can build a wall in the way, or the colonist can be wounded by a previously unseen sniper. The list just goes on and on.

Then there's decision-making to consider: What should a colonist do? Do some work, get some food, or put out a fire? What if someone else already is, or it's far away, of there's a muffalo raging near it? How do evaluate between all these priorities? “I've had to learn and develop some pretty complex AI systems to handle all of it, and I'm proud of those,” says Sylvester. “Thankfully, I had some experience with this as a designer on BioShock Infinite.”

Rimworld By Ludeon Studios

In going out on is own, Unity has provided Sylvester with the framework to build his ambitious project. “I chose Unity early on just because it was so recommended,” he recalls. “It was my technical basis for all of the five or six other game prototypes I did before starting RimWorld, and it's been very useful.” He uses popular Unity Asset Store plugin UnityVS to integrate with Visual Studio, and calls it a lifesaver.

Sylvester takes advantage of what the software has to offer, and what it doesn’t. “I actually abuse Unity pretty hard; I mostly don't use its built-in object/component framework, instead working with a custom 2D tile-based framework I coded myself,” he says, noting that he didn’t use Unity’s 2D tools because the game predates them. “Even so, Unity does a great job of abstracting out all the irritating tasks involved in managing and importing content, producing builds for different operating systems, profiling, handling shaders and graphics drivers, keyboard and mouse input, and so on. I recommend it to anyone who asks.”

“On the purely technical level, it was easy,” he says of RimWorld’s earliest days. “It took just a few months until the game was working and breathing in a meaningful, playable way.” Coming up with the working design, however, wasn’t quite so easy. “[It] was hell. I had to iterate through five or six different games at two months each, throwing them out one after another, wondering if my dreams of indie developerhood were destined to end in failure. But once I had RimWorld going, it was obvious that it was something special.”

When he initially started working on the game, he put it on a sparse, arid planet because it suited the theme and gameplay. It fit so well, in fact, that it informed the thematic underpinning for the entire gameworld. “It immediately looked like the Old West,” he recalls. “It seemed obvious to take it in a Firefly-influenced direction.”

Despite having worked on huge titles like BioShock Infinite, Sylvester learned game design by creating Unreal Tournament mods, and for this reason says shoestring development has always been his home. Still, the life of an indie game designer takes some getting used to. “Most of all, I find it's absolutely crucial to prioritize,” he says. “I keep a 50-page prioritized list of everything I want to do in RimWorld, and I re-evaluate it constantly. Do I really need to do that thing more than everything else in these 50 pages? Really? Maybe I can ship without it. Yeah. I can ship without that.”

“It's amazing how much you can simply not do and still have a fun, functioning game,” he continues. “The first release of RimWorld is missing a lot of really basic features, but the things that really matter are all present, well-designed and well-tuned.”

The other thing he has prioritized is basic competence across the board. “For example, I did all the art and sound in the RimWorld pre-alpha,” he says. “They're not pro quality, but they're not hideous programmer art. You can do pretty well with simple, straightforward art assets. It beats having to beg others to do every menu icon and menu interface beep.”


The public version of RimWorld that’s out now was developed entirely by Sylvester. But thanks to a spectacularly successful Kickstarter campaign (see sidebar), he’s hired some collaborators to pump up the game's audio and visuals, and is also actively looking for help with programming and design.

When asked what he’s been happiest about in developing RimWorld, Sylvester’s answer is very simple: “The fact that it works!” he says. “Having failed to do that a bunch of times in a row, I'm really happy to have made a game that's compelling at the most basic level. That was the really hard part—the rest is gravy.”


Like many an indie game in recent years, RimWorld exists in large part thanks to an overwhelming response to its Kickstarter campaign. “I was surprised,” developer Tynan Sylvester says of the crowdfunding experience. “I remember discussing the goal with my girlfriend before release: Could we really make $20,000? That's a lot of money! Wouldn't it be crazy to make like $100,000?” And surprised they were: the game ultimately earned $262,132, far exceeding all expectations.

Where the Muffalo Roam

The illustrious muffallo play a prominent role in RimWorld. They're basically big, blue alien buffalo, and they wander around the gameworld eating grass. Developer Tynan Sylvester remembers a particularly funny moment involving the creatures: “Muffalo and people had found their food using separate pieces of code,” he says. “One day, I decided to unify these, and I did—I got them both running off the same behavior tree nodes.” But he didn't disable something that he should have: “One of the muffalo got hungry. He walked up to the colony, and smashed on the door until it collapsed. He then walked in, made his way to the meal room, took a nutrient paste meal from the dispenser, sat down at the table where another colonist was eating, and began enjoying his meal.” A very civilized muffalo, indeed.

A sci fi colony sim driven by an intelligent AI storyteller.

RimWorld follows three survivors from a crashed space liner as they build a colony on a frontier world at the rim of known space. Inspired by the space western vibe of Firefly, the deep simulation of Dwarf Fortress, and the epic scale of Dune and Warhammer 40,000.

Manage colonists' moods, needs, individual wounds, and illnesses. Engage in small-team tactical gunplay. Fashion structures, weapons, and apparel from metal, wood, stone, cloth, or futuristic materials. Fight pirate raiders, hostile tribes, rampaging animals, giant tunnelling insects and ancient killing machines. Tame and train cute pets, productive farm animals, and deadly attack beasts. Watch colonists develop relationships with family members, lovers, and spouses. Discover a new generated world each time you play. Build colonies in the desert, jungle, tundra, and more. Manage quirky colonists with unique backstories, traits, and skills. Learn to play easily with the help of an intelligent and unobtrusive AI tutor.

For Windows, Mac, Linux. The game is distributed by DRM-free download. RimWorld is developed by Tynan Sylvester and Ludeon Studios, and we've been improving it since its first public release on November 4, 2013.

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RimWorld is not designed as a competitive strategy game, but as a story generator. It's not about winning and losing - it's about the drama, tragedy, and comedy that goes on in your colony. The game creates events like pirate raids, trader arrivals, and storms. But these events aren't random. RimWorld uses an AI Storyteller (modeled after the AI Director from Left 4 Dead) who analyzes your situation and decides which event she thinks will make the best story.

There are three storytellers to choose from: The carefully-paced Cassandra Classic, the slower-paced, building-oriented Phoebe Chillax, and the totally unpredictable Randy Random.

In RimWorld, your colonists are not professional settlers – they’re survivors from a crashed passenger liner. They'll be accountants, homemakers, journalists, cooks, nobles, urchins, and soldiers.

A nobleman will be great at social skills (for recruiting prisoners or negotiating trade prices), but refuse to do physical work. A farm oaf knows how to grow food, but cannot do research. A nerdy scientist is great at research, but cannot do social tasks at all. A genetically-engineered assassin can do nothing but kill – but he does that very well.

Each character has personality traits. Neurotic colonists work faster, but are more stressed and prone to mental breaks. Abrasive characters will interact poorly and harm the mood of those around them. A nudist loves to be naked, while a cannibal gets a rush from consuming human flesh.

Colonists develop - and destroy - relationships. Each has an opinion of the others, which determines whether they'll become lovers, marry, cheat, or fight. Perhaps your two best colonists are happily married - until one of them falls for the dashing surgeon who saved her from a gunshot wound.

You’ll acquire more colonists by taking in refugees, capturing people in combat and turning them to your side, buying them from slave traders, rescuing them, or taking in migrants.

Wounds, infections, prosthetics, and chronic conditions are tracked on each body part and affect characters' capacities. Eye injuries make it hard to shoot or do surgery. Wounded legs slow people down. Hands, brain, mouth, heart, liver, kidneys, stomach, feet, fingers, toes, and more can all be wounded, diseased, or missing, and all have logical in-game effects. And other species have their own body layouts - take off a deer's leg, and it can still run on the other three!

You can repair body parts with prosthetics ranging from primitive to transcendent. A peg leg will get Joe Colonist walking after an unfortunate incident with a rhinoceros, but he'll still be quite slow. Buy an expensive bionic leg from a trader the next year, and Joe becomes a superhuman runner. You can even extract, sell, buy, and transplant internal organs.

Diseases are a serious threat. Open wounds will get infected. Flu and plague can appear anywhere, and tropical rainforest areas are rife with malaria and sleeping sickness. As colonists age, they can develop chronic conditions like cataracts or bad backs.

Temperatures are modeled both outdoors and indoors. As the seasons turn, the outdoor temperatures will rise and fall. Plants only grow in some temperatures. When it gets cold, it will snow. People can get hypothermia or heatstroke.

You can control indoor temperatures with heaters and air conditioners to aid survival and comfort, or prevent food from rotting. You can even build deadly temperature traps to cook enemies alive.

The game generates a whole planet from pole to equator. You choose whether to land your crash pods in a cold northern tundra, a parched desert plain, a temperate forest, or a steaming equatorial jungle.

Different areas have different animals, plants, diseases, temperatures, rainfall, mineral resources, and terrain. The challenges of surviving in a disease-infested, choking jungle are very different from those in a parched desert wasteland or a frozen tundra with a two-month growing season.

You can tame and train animals. Lovable pets will cheer up sad colonists. Farm animals can be worked, milked, and sheared. Attack beasts can be released upon your enemies. There are many animals - cats, labrador retrievers, grizzly bears, camels, cougars, chinchillas, chickens, and more, as well as exotic alien-like lifeforms.

RimWorld uses an engine that was originally developed to power a tactical combat sim similar to Jagged Alliance 2. This means it has a lot of features designed to make small-team firefights interesting. For example:

  • There's a cover system that models low cover and leaning around corners.
  • There's a really nuanced algorithm for determining and reporting hit chances based on distance, skill, weapon, lighting, angle, and cover.
  • Weapons have some pretty deep stats.
  • The AI plans and executes tactical moves like flanking while trying to stay out of the enemy's line of fire. It uses a number of heuristic algorithms to analyze the battlefield and use the space effectively. It works with allies and avoids bunching up.

Because of how important cover and positioning are in gunfights, combat interacts deeply with the colony's layout and structure. Players have to think about how they want to position their constructions to maximum advantage in future firefights, and it's possible to build a wide variety of base configurations for maximum tactical advantage against diverse foes. Combat in general is a lot more interesting than the traditional trading of blows you might expect in a base-building game.

Rimworld By Ludeon Studios

This kind of game can be really hard to learn. So we've created an adaptive teaching system that watches your actions to figure out which parts of the game you understand, and teaches the parts you're missing. If you don't understand a control, the game will notice and help you out unobtrusively. If you already know something, the game won't interrupt you.

RimWorld also uses a notification system to make sure you don't miss anything that needs looking at. If you're low on food, or a colonist is about to go berserk, a message hovers in the corner of the screen informing you of the fact. No more getting annihilated because you missed some little detail. If you get annihilated, it'll be for a totally legitimate reason.

People in RimWorld constantly observe their situation and surroundings in order to decide how to feel at any given moment. They respond to hunger and fatigue, witnessing death, disrespectfully unburied corpses, being wounded, being left in darkness, getting packed into cramped environments, sleeping outside or in the same room as others, and many other situations. If a colonist is too stressed, they might lash out or break down.

When a colonist becomes too stressed, they may suffer a 'mental break'. Some will give up and wander the colony for a time. Some will leave. And some will, in dwarfish fashion, become psychotic and throw a violent tantrum.

The flavor of RimWorld is a mix between hard sci-fi and the Old West. It's a rim world at the edge of known space, far from the civilized core worlds. The planet is vast and mostly empty, and there are no strong civilizing authorities anywhere nearby. You're on your own.

The core idea in the RimWorld universe is diversity of human conditions. In this setting, humanity is spread across the galaxy, yet lacks any way of traveling or communicating faster than light. Combined with the fact that stellar civilizations regress (due to war or plague) as often as they progress, this means that someone traveling between stars may end up interacting with people at any level of development, from pre-agricultural tribes to transcendent machine gods.

Your starting colonists in RimWorld are at a technological level in the middle of this span. But you may end up interacting with people at much lower and higher levels, as well as acquiring and using their tools and weapons. In RimWorld, a single fight can involve a bow and arrow, a shotgun, a charged-shot pulse rifle, and a biomechanical killing machine.

All versions can be immediately registered on your Steam account through the automated Steam registration system.

Full Game Pack ($35)

Instant access to the game.

Plus, get the Prototype Pack of five early game designs that eventually became RimWorld.

Name in Game Pack ($50)

Put a name (probably yours) into the game and appear as a pirate raider, colonist, traveler, or trader. Players will recruit, command, and fight you for all time! Includes the Full Game Pack.

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Please get your parents to buy the game for you if you're under 16.

Be sure to read the end-user license agreement and privacy policy to make sure you agree before purchasing.

Please note that player-created content must follow the creative rewards guidelines.


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