Anomaly expansion and update 1.5 announced!

Posted March 13th, 2024 by Tia Young

Sanity-shredding perils abound in this new horror-themed expansion

We’re super excited to announce our new horror-themed expansion, RimWorld – Anomaly!

This expansion adds all manner of monstrous, mysterious, and maddening threats, containment facilities to capture and study dark entities, and a new reality-twisting endgame. Anomaly releases in one month!

We’re also announcing the upcoming update 1.5 to the base game (which will be released at the same time as Anomaly). You can currently test this update on the unstable Steam branch – see the bottom of this announcement for details. (Note that this is only base game content – Anomaly is not yet available.)

We’ll be releasing more info about Anomaly in a series of blog posts over the next few weeks.

Spoiler warning: Below is a high-level description of the expansion content. There are some spoilers here.


The expansion begins when your colonists accidentally provoke a mad superintelligence. From then on, madness manifests: Monstrous creatures, mind-bending mysteries, infiltrating parasites, and sanity-shredding phenomena that twist the whole world around you.

Inspired by classics like Cabin in the Woods, The Thing, The Cthulhu mythos, Hellraiser, and many more, Anomaly goes beyond fighting monsters. This expansion presents ominous, puzzling, mind-controlling, and earth-shaking threats to build your personal horror story.

Some of the twisted scenarios you’ll encounter:

  • At night, hear the screeching of a psychically-invisible hunter that feeds on human souls. Build proximity alarms to detect when it’s near, but you can only fight it when it chooses to reveal itself. Chip away at its health every time it returns, and collect and study chunks of its flesh. Turn the tables, become the hunter and kill it where it sleeps.
  • A massive flesh creature is growing across the landscape, consuming and covering the whole map with a quivering mass of meat. It defends itself with beasts and acid. Fight it to get samples of its nervous system, then study them until you can venture to its heart and kill it for good.
  • A parasite has mind-controlled some of your colonists – but who? They pretend to be human as they work to infest others. Track evidence, imprison, interrogate, and medically test people to find out who is infested before it’s too late.
  • A pulsating obelisk crash-lands near your base. You can try to suppress its filthy energy, but the obelisk may lash out and violently mutate your people, copy them endlessly, or abduct them to an endless gray maze.
  • Your colonists become obsessed with a beautiful golden cube, one by one. They build statues of the cube. They worship the cube. They love the cube.
  • A corpse arrives that looks exactly like one of your colonists – and seems to follow them. No matter what you do, the corpse returns…
  • And many more weird and horrifying events!

Horror combat

You’ll fight battles against shrieking fleshbeasts, hordes of shambling undead, spherical death-machines, massive devouring water-beasts, lumpen imitations of human beings, and many more nightmarish perils. Use the monsters against your normal human and mechanoid foes where you can!

Construct new tools and gear to help you – flamethrowers and hellcat rifles, IEDs that resurrect the dead, flesh-mutating pulsers that transform living creatures, insanity-inducing weapons, and crossbows that stun your targets.

Capture and study entities in your facility

To defeat the monolith’s manifestations, you must gain their power. Build a grand containment facility so you can capture monsters, study them, and exploit them. Expand it with stronger walls, floors, and doors to keep them secure. Exploit your captives to use their power against your enemies – but don’t push them too far!

Harvest the new bioferrite and shard resources from your malevolent menagerie to use in experimental serums, psychic rituals, ghoulification surgeries, and void-powered constructions.

Fight the cultists who serve the machine-mind

Macabre cultists will attack and perform their psychic rituals with suicidal commitment. They may stand in rows, or chant around a ritual circle, or whisper hateful psychic curses against your colony. Destroy them before they summon bloody beasts, abduct your people, or drive you mad with psychic influence.

You can use the same rituals for your own purposes. Summon the massed dead, rain rage-filled blood, connect with the void, steal the minds and health of your foes, and more.

Choose your fate in a new endgame

In the end, the abyssal void will swallow the world and you must choose your fate.


Ludeon Studio’s founder Tynan on why he decided to make Anomaly:

“I wanted to give players new kinds of emotions they haven’t encountered before in RimWorld. We’ve explored feelings around dramatic combat tension, family warmth, problem-solving and many more. Now I wanted to provoke new emotions – dread, psychological tension, suspicion and mystery. The horror theme unlocks a new emotional landscape for us to explore.

There aren’t many games which mix management and horror either, so it was an interesting design challenge to marry these two elements.

Plus I saw Cabin in the Woods and I thought the monster lab was awesome.

It was important to me that this not just be a collection of monsters to shoot at, because the base game already generates those feelings of combat tension and I wanted something new. So we made sure to design the new threats to follow the arc of classic horror stories: The protagonists encounter a mystery, then realize it’s a threat, and try to survive while they learn more about it, slowly building advantage before they try to turn the tables. It’s a very RimWorld kind of chaos when several of these things are happening at once with different threats.

This was really fun to work on and I think the team did an awesome job – I can’t wait for everyone to play it.
– Ty”


We have a lot to say about update 1.5 – it’s been nearly 18 months of work!

If you’re interested in trying update 1.5, you can play on the unstable Steam branch. To get access, go to your Steam library, right-click RimWorld and select “Properties”, then select the BETAS tab and choose branch ‘unstable’. Restart Steam if your game does not automatically update.)

Modders should be able to use this public 1.5 unstable branch to update their mods before update 1.5 is released to everyone next month.

Read the full 1.5 changelog here (18 pages of changes!) or read the summary below.

Books, bookcases, couches, ornate doors: There are now books for your colonists to read, and bookcases to store them in! Books are great for recreation and for their unique bonuses: textbooks increase a specific skill, schematics progress a certain research project, novels increase recreation faster, and tomes progress an Anomaly-specific research project. You can obtain books from traders or as quest rewards. Storing books in bookcases increases the beauty of a room, makes nearby research benches faster, and increases the XP and recreation gained from reading.

Couches function like armchairs but now have room for two! And ornate doors are the first 2×1 door in RimWorld (it took some work for the system to support doors that weren’t 1×1!). They’re very fancy and suit throne rooms, temples, or other prestigious buildings.

Wall lamp, flood lights, and hidden conduits: Yes, you can now put lights on your walls and hide your conduits! Wall lamps and wall torches can be placed directly on walls. They function like a floor lamp or torch would, but with a little less light. Flood lights are very powerful (and expensive) outdoor lights that cover large areas, which saves you from building several small lamps. Hidden conduits are useful for two reasons: they’re harder to damage from explosions or fire, and they’re invisible to the player unless you’ve got the power/building UI turned on.

Performance improvements: We’ve continued to work on optimizing RimWorld’s performance. Pawns (characters and animals) are now drawn in parallel on a separate thread, the pawn render system was rewritten to allow for easy addition/removal of visuals, and lots of optimizations were done on alerts, beauty calculations, and pen animal food-searching behavior.

Crawling: When downed, humans can now crawl on the ground! Crawling colonists leave blood trails, move away from danger, and will seek out the nearest place to recover, like a hospital bed or sleeping spot. You’ll see enemies crawling around too. It’s rather dramatic.

Possessions from traits: When choosing your starting colonists, there’s now a chance for them to spawn with possessions related to their traits. For example, a psychopath might carry a human heart, or a pyromaniac comes armed with molotovs, or someone who’s greedy could have pockets full of gold.

Mechanoid water emergence and slag chunks: Did you think the water was safe? Mechanoids can now surface from bodies of water, which requires adapting to oceans and lakes when building your base’s defenses. Also, certain large mechanoids have a chance to drop a “mechanoid slag chunk” when they’re broken down – these act like steel slag chunks and can be smelted for steel.

Bionic jaws and organ decay: Sometimes colonists lose their jaws in a terrible accident, but they can now be replaced with the new bionic prosthetic. Keep an eye on your colonists’ organs too – there’s a chance they may develop a very rare organ decay disease.

“Mine vein” designator: This command orders colonists to mine out a whole mineral lump in one click. For example, if you just want to mine gold ore and want to ignore the surrounding rock, the “mine vein” tool tells colonists to mine all the visible gold plus any gold that gets revealed in the process.

Clean room: Selecting a colonist and right-clicking a room that’s dirty now gives you the option to clean the room. This is far more convenient than manually clicking dirt on the floor and queueing up cleaning actions.

New wanderers after a “game over”: When all of your colonists are dead or gone, there’s a new option as part of the game over letter to “create new wanderers”, if you want a second chance with your colony. This allows you to create 1-6 new colonists to inhabit the remains of your colony instead of ending the game. This is entirely optional and you don’t have to use it if you prefer a more hardcore experience.

Search function: In the bottom right corner, there’s now a magnifying glass icon and a search bar you can type in to find items, structures, enemies, etc. on your map. No more losing items! The default hotkey is “Z”.

Tainted apparel visual changes: Tainted apparel (clothes worn by someone that has died) now has a distinct, darker color. Previously, it was easy to mix up tainted apparel with non-tainted apparel.

UI improvements: There’s an option to make colonists’ moods on the colonist bar much more visible. When you zoom out very far, pawns become highlighted so they’re easier to spot on the map. We also redesigned the prisoner and health tabs and improved the research UI and policy UI for a better experience.

Art improvements: There’s new and improved weapon art. We also added new immature crop art and leafless tree art for the plants missing those.

Miscellaneous: There are lots of smaller things that were done for 1.5 (see the 18-page changelog), including an option to capture carried pawns without having to drop them, improved construction hauling, and better firefighting.


Please wishlist Anomaly!

And stay tuned for our Anomaly feature blogs as we approach release day (which is in one month)!

Anomaly has more content than any previous expansion. We expanded the team and worked for 18 months on this expansion and update 1.5, so it’s got a lot of passion in it!

Anomaly adds new feelings to RimWorld. It creates moments of terror, new roleplaying opportunities, unforgettable stories, and a unique narrative experience for every player. We seriously cannot wait to let you get your hands on it.

In the meantime, we’d love to hear what you have to say about Anomaly and update 1.5!

  • Join the discussion on Reddit
  • Share your thoughts on X (formerly Twitter)

If you’d like to help us test the 1.5 unstable build and report bugs, please join the official RimWorld Development Discord.

See you soon!
Ludeon Studios

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