While the focus in RimWorld is on the stretch of land that you’ve claimed for your base, the entire planet is available to you to explore. You can see the spread of different biomes and factions when you select your landing site at the beginning of the game, but really exploring and interacting with the broader world is dependent on either sending out risky caravans or developing later-game technologies like drop pods and (now with Odyssey) gravships. For our System Hack, the base site is likely to feel a bit smaller, and venturing out onto the world map is something that happens sooner. Luckily, we have decades of wilderness exploration in TTRPGs to help us out. When looking at our overworld map, we want to make sure that exploration and venturing beyond the base site both provides interesting decisions and helps us populate a world with people and places that our players will want to explore.

The overworld is also where we start considering some of the setting assumptions of RimWorld, and deciding where we converge or diverge. RimWorld’s implied setting is fascinating, but the place where all of the setting ideas fail to emulsify is in the overworld. Beyond the dispersion of settlements being a clear game contrivance, the lack of any population buildup or agglomeration is just not how any planet would look after years of colonization. There is a line to be walked here; a ‘RimWorld’ would likely self-select for individualists who may want space and to be left alone, but there’s simply too many personal and economic benefits for larger settlement to assume there wouldn’t be any.

When you start a game of RimWorld, you select a spot on the world map to place your colony. While we could generate a world map to start our game as well, starting location generation could just as easily happen from a set of options. Given the size of a RimWorld planet, pretty much every permutation of biome, proximity to settlements, and proximity to water features is available. For a paper game, the parameters of the local map can be set by selecting a biome, a degree of rockiness/mountainousness, proximity to a road, proximity to a river, and proximity to a body of water (with that decided between lake and ocean). Those options would determine how map hexes are generated, as well as other elements like prevalence of stone, metal, and wood resources that would show up in the local hexes.

For local hexes, we’re going to once again adapt a set of map tools that I particularly like for hex map generation. In The Welsh Piper’s Hex-based Campaign Design, Each 25 mile Atlas Hex is broken up into 5 mile subhexes which are then generated using the tools in the article. We’re going to use the hex/sub-hex structure here as well, but instead of 5 mile and 25 mile hexes we’re going to be zooming in to one mile and five mile hexes. The intent here is to model the area immediately surrounding the colony, so instead of looking at travel at a scale of days we’re looking for travel at a scale of hours. We don’t need to do anything fancy with biomes (assuming the whole five mile hex is one biome is fine), though we could identify whether each hex is wooded, a clearing, or mountainous. From there, we can set inventories of key resources, namely wood, stone, and metals.

Heading out to the main hexes is where we can start using some of the biome generation tools detailed in Hex-based Campaign Design, but also take into account those river and road options. Rivers and roads are a first step to the next major element, which is going to be the location of other settlements. As mentioned above, there is potential for a much more diverse set of settlements, and even if we keep the assumed population relatively sparse, neighboring settlements could take on a number of forms. There will be other colonies, yes, but also trading posts, ports and spaceports, and potentially larger towns. This will also mean that factions will be treated differently as well. The presence of larger factions made up of multiple settlements will not necessarily be the norm, but the presence of a larger town may also imply the presence of a faction. Figuring out balance of power may be a bit more complicated, but if key groups or factions are decoupled from settlements, it introduces a lot of interesting storytelling opportunities. Powerful families may make up a single settlement or have influence over multiple settlements, while a mercenary company could end up being a de facto government if they provide protection services to a town or network of settlements. The important thing will be making engagement with other groups an interesting part of the game, as well as lending a space western feel to the whole thing which is implied at a low level in RimWorld.

Another thing in RimWorld which should be part of the overworld is the presence of points of interest. There is an implication in RimWorld’s implied setting that there are constant cycles of colonies being formed and destroyed, resulting in ruins all over the map. Not only does this provide a constant stream of interesting map features and ‘ancient dangers’ to find, it implies a lot about the dangers of ‘the Rim’ and how few colonies make it. That level of danger and level of survivorship should be reflected in the faction mechanics as well as points of interest; factions that are powerful enough to influence swathes of territory and multiple settlements have likely been around a while, and have some form of continuity built in, whether that be family lineage, succession rules, or even democratic elements. Meanwhile, new upstarts are more likely to be disruptive, upsetting the balance of power and making enemies.

But let’s go back to the points of interest. Points of interest should imply something about the history of the planet, and it may even be a map option to determine how long the planet has been settled. Younger planets may have points of interest like starship crashes or unique geological deposits, while older ones are more likely to have abandoned colonies or spaceports and hidden cryosleep vaults akin to the typical ‘ancient danger’ on a RimWorld map. And similar to RimWorld, the likelihood of a point of interest being close to a colony should be relatively high.

The final consideration of our game’s overworld is going to be those non-human populations. RimWorld assumes most animals are close to their Earth equivalents, with some obvious expansions (like the boomalopes). Animals can mostly be tracked by biome, but there’s also the question of the major antagonist populations, the insectoids and the mechanoids. My general thought is that we don’t necessarily want to have an encounter balancing mechanic in our System Hack, but that does mean that the presence of insectoids and mechanoids could make things very dangerous, especially in the early game. Mechanoid threats seem to be the sort of thing that is broadcasted; even if mechanoids aren’t assumed to be under human control, they’re dangerous enough that any colony would receive warning that there’s a mechanoid threat. There’s also going to be more of a push to make the dangers expected, or at least a consequence of another action. Deep drilling could cause an insectoid infestation, and random mechanoid threats may come in the form of space debris or ‘ancient dangers’ that won’t necessarily activate unless disturbed. Like in RimWorld, though, colonists will always have the option to flee a colony that they aren’t able to save from one of these threats.

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The game’s overworld should be interesting, but we are implicitly asking a question of whether managing the colony or exploring the world are going to be the primary activity of the game. The intent is the former, but so much of the extant RPG hobby looks more like the latter, which is at least worth noting before putting all the options out and being surprised that more exploring is happening. Still, good exploration will make the game more engaging, and so long as reasons to venture out of the colony are being provided by the needs of the colony, everything ties together. This is also going to look a bit different than RimWorld; while there may be orbital traders and wandering caravans, players will have control over how close they are to roads and even other settlements. A game taking place in miles of wilderness is going to be quite a bit different from a game taking place on the edge of settled territory near a large spaceport. Part of the key of overworld mechanics is giving options, and figuring out how easily the rest of our systems will handle these options.

At this point, our System Hack begins to shift from abstract to specific. While using Cortex Prime means a lot of the rules scaffolding already exists, it’s now time to start plugging things in and building out what we want all our assumptions to actually be. It’s time for The Lists. In 2026, we’re going to jump to the next stage of implementation, and begin to turn Colony Sim Cortex from ideas to Alpha. Join me next month and the rest of 2026, and let’s see what we can do with this System Hack!

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