Hotfixed to Alpha11c (Update: Alpha11d)

Posted July 22nd, 2015 by Tynan Sylvester

Alpha11c is a very small hotfix to Alpha11b that fixes a few serious bugs. All save games and mods should still be compatible.

Update: Now to Alpha11d. This is the same as Alpha11c, but the save game location will be correct on Macs. (I originally built Alpha11c against a slightly old version of Unity from before they changed the save game path).

There will not be a new email sent. You can download using your previous link from your last email. Your personal download link is permanent and always has the latest version. If you need help getting your link, please go to


  • Mitigated a game-killing bug caused by corrupted pawns. The corrupted pawn will now be destroyed instead of causing broken saves and game crashes. I’m still tracing the root cause of this so I can make the game not generate corrupted pawns in the first place.
  • Fixed a stuck-pawn bug caused by wardens trying to recruit downed prisoners and immediately ending their job, over and over.
  • Fixed prisoner config resetting at inappropriate times.
  • Fixed floor smoothing speed being determined by mining skill (it’s now construction).
  • Fixed repeated EMP damage canceling stuns in progress.

Quick update upcoming developments

Posted July 22nd, 2015 by Tynan Sylvester

Hey everyone, hope summer treats you well. So here’s the state of development now:

First, players found some rare but game-killing bugs in Alpha 11b. As in, they can actually kill your save game and make it unloadable. I’ll probably be releasing a small, non-essential hotfix to Alpha11 to fix these. This will be a minimal fix with no new content or changes to compatibility.

Second, Alpha 12’s key feature will be animal husbandry and related features. It’s an ambitious update: new animals, animal mating, reproduction, egg laying, species life stages with different labels, appearances, and statistics, perhaps animal training, attack animals, and so on. Piotr is also working on some other juicy features: new varieties of one-use ancient artifacts for psychic attacks and control, a new room stats system so pawns get happier when they have impressive rooms and heal better in sterile hospitals, and passive ‘facility’ buildings that enhance the function of other nearby buildings.

So I think Alpha 12 will be an important update, but it will take some time. It might not be finished before the end of August, in which case it’ll have to wait until 2016 (since I’m taking a break starting in September). I considered just releasing what we have but I really don’t want to release animal husbandry in a half-done state. I want you to experience the glory of it all at once.

In general everything’s been going great, and work is progressing rapidly. Currently I, Piotr, Rhopunzel, and Al are all working on RimWorld, so great new stuff is getting slammed in every day. It’s fun!

And now, a picture of wargs and Yorkies next to a pile of corpses.



Alpha11b released

Posted July 4th, 2015 by Tynan Sylvester

I’ve just released RimWorld Alpha11b! This is a fix-and-adjust build without crazy new features. You can still load saves from Alpha 11 (though they will report some errors on loading and have a few minor issues around load time, they should play fine in the long term).

Mods might become incompatible. I’ve tried to keep the API the same as it was before, but a few places have necessarily changed. Also, since the DLL was recompiled, the ABI might not be identical. This means the functions and variable names are the same, but the compiler might have changed the way the bits and bytes are passed around, causing code compiled against the old DLL to not work properly when it tries to talk to the new DLL. This means:

  • Simple mods (especially those which are purely XML data, images, and sounds without any code) should still work without any changes.
  • Mods with code might work without changes, but there’s a good chance they’ll need to be recompiled against the new DLL.
  • A few mods will actually need to have code changed if they touch parts of the API that I changed.

If you own the game, you can get the new version by re-downloading from the link you used before (it is a permanent link and always has the newest version). Anyone still having trouble should start at the support page. A new email will not be sent for this update.

Full change list:

  • Colonists will now try to avoid pathing outside their allowed area.
  • Open doors equalize temperature faster.
  • Much, much smarter sapper escort AI.
  • Sapper now avoid mining high-health ore while finding tunnelling paths.
  • Reorganized and clean up options menu and graphics settings.
  • Mods config page shows load order of mods.
  • Toxic fallout kills plants much more slowly.
  • Enemies (especially wargs) now ignore unpowered unmanned turrets and mortars.
  • We no longer allow buying back prisoners you just sold as a way to insta-recruit anyone.
  • Can no longer sell rotten items.
  • Treatment result is now indicated with a text mote, not a global message.
  • Adjusted a bunch of sound volumes.
  • Fixed pirate merchants only bringing slaves when population is high. This should be reversed.
  • Reworked how slave prices are calculated so they take injuries, capacities, and skills into account better.
  • Colonists now harvest planted trees on their own.
  • Optimizations to grower work scan algorithms.
  • Cleanup on main menu background image.
  • Smelt slag recipe can use do until you have X.
  • Siegers can never use melee weapons (too exploitable).
  • New sound: warg voices.
  • New sound: treatment.
  • New sound: medicine used successfully.
  • Player-created backstories and translations have been updated.
  • About 150-200 bugfixes – some big, some small.

Steam release moved to 2016

Posted July 3rd, 2015 by Tynan Sylvester

So after some great conversations about the Steam release and some more thought, I’ve decided to hold off on the Steam release until next year.

Originally, I wanted to get the Steam release out so you would all have access to Steam features and automatic updates while I was on break. To alleviate concerns about me not being around for my break, I thought I’d write a blog post describing the exact state of the game and where development was heading. The idea was that anyone could read it and decide for themselves whether they wanted to buy the game or not.

However, on further discussion it seems like a risk. These days, people assume a lot about a developer and their process very quickly, and a lot of it can be negative. A lot of people have been burned. So no matter how much I communicate, a lot of those messages won’t be read, understood, or even believed. I hope I’ve built up some trust among RimWorld players by my actions in the past – but with a Steam release come a lot of new players who don’t know me from a hole in the wall. My fear is that misunderstandings and accusations around me taking a break soon after release would taint what I think will be an otherwise strong release on Steam.

The benefit of pushing to Steam now doesn’t seem worth it. Steam Workshop is nice, but a lot of people don’t use it even when they have the option. Automatic updates are cool, but there’s not much point when the game isn’t being updated because the developer is on break. We already have a well-working release system that’s served us all well for almost two years. So there’s just no great hurry there that outweighs the risks.

I’m sorry for the confusion on this and I hope this isn’t letting anyone down too much. Of course, the game itself will be the same either way (in fact, we might get more content out in the near term because of time saved from Steam release hassles). I also really appreciate everyone who took the time to write out a full set of thoughts on this topic. You’re not just giving me two-line low-effort responses; you’re giving me entire essays, and it’s really useful. I am listening and learning from you guys all the time.

In other news, Piotr Walczak, Polish coding prodigy has rejoined me after his school year. You may remember him as the guy who wrote the original code for the health system last summer. Having him around should help increase development speed.

Alpha11b is approaching final testing. It’s a massive bugfixing, tuning, and adjusting release, with hundreds of bugfixes and many balance changes and other small improvements. It’s also compatible with Alpha 11 saves! So look for that to come out soon.

On the upcoming Steam release

Posted July 1st, 2015 by Tynan Sylvester

The news that people have been asking me about for years is finally here! I’m planning on releasing RimWorld on Steam Early Access around the end of July or early August.

(Edit: Having considered the feedback so far, there’s a good chance I may release the game on Steam as a non-Early Access finished game. Read below for why. Nothing of substance would be different from how it’s described here – it’s just a labeling/PR issue.)

At that time, the key distributor will be set up to give out Steam keys to qualifying existing buyers (currently it only gives your non-Steam download links). I’ll try to get the keys up at the same time as the Steam release, but be warned that there might be a day or so of delay. In either case, the content will be the same on and off Steam.

Steam Workshop will be supported from day one of the Steam release, so it’ll be extremely easy to subscribe to mods. In fact I’m a little worried that people won’t come to our thriving mods forum any more! But I think it’ll be okay. A community this awesome is about more than just getting the mods.

In the run-up to the Steam release, I’ve been focusing my efforts on perfecting what there is of RimWorld rather than biting off chunks of new content. If you read my changelog you already know that I’ve been obsessively bugfixing for a month now. As I mentioned in the Alpha 11 release video, I’m pretty satisfied with the shape of the game. Up until Alpha 11, there were always big holes in the design. Back in the days of yore it was the lack of real hauling and stockpiling (resources were stored in hammerspace, like StarCraft II). Then it was the monotony of a single enemy type with a single strategy. Then the monotony of a single biome. As each piece was added, it filled in a missing piece in the design. The last hole was the one represented by the all-powerful killbox strategy which funneled dumb enemies into a single turret-lined room. Alpha 11’s new sapper strategy solved that.

Now, for the first time, I look at the design and I don’t see gaping holes that need to be filled. Of course, there are still countless things that could be added to the game. I have a document listing hundreds of them. But they all feel optional to me. What’s there is a rounded, integrated design. In my mind the design always used to look like an irregular lump of Swiss cheese; now it’s more-or-less rounded and more-or-less smooth.

So is it done? I’ve thought a lot about what it means to call a game “done”. Ten years ago, a game was done when it was printed to disc. But with digital distribution, we never lose the ability to keep changing a game. So when is a game done? Is it just when you stop adding things? No, because a game can be abandoned without being finished. Is it when there’s nothing else that could be added? That’s not reasonable; I could work on RimWorld for 50 years and never satisfy that. In the end, I think that a game is done when promises have been fulfilled, and there aren’t holes in the design. And we’re reached that point, so RimWorld is done.

That said, just because RimWorld is done doesn’t necessarily mean I’m done with it.

I like working on the game, you all like playing it, and it’s profitable. So I probably will add more content to the game. In the meantime, though, I think it’s time for a bit of a break. I’ve been working on RimWorld and its prototypes for going on three years straight now, and my hours are usually pretty long. I’m starting to feel a bit of burnout. I often seem to develop this dull ache behind the eyes after a couple hours of work. I have trouble concentrating for the lengths of time that used to be normal for me. For that reason – and just because I believe in having a life that isn’t all work – I’m taking some time off from full-time RimWorld development starting in September. Currently it’s looking like it’ll be about six months. I’ll still be around to interact, but I won’t be developing constantly like I have been.

I can’t say exactly what will happen when I return. I might just take the feedback from the Early Access release, integrate it and release RimWorld 1.0 without major new features. Or, I might continue developing the game for years. As I said, I like working on RimWorld, but I’ve also learned that the future is very uncertain and it’s a bad idea to make promises you’re not sure you can keep. That’s part of why I’m telling you about my break now, before the big Steam release. In any case, as always, I encourage people to only make buying decisions about the game based on what it is today. Please don’t ever buy any game – including mine – based on a guess at what it might some day become. Hype trains crash a lot.

So – that’s all the news! I also want to say thank you. There are a lot of scary stories about indie development, and back when I quit Irrational I wasn’t looking forward to facing the poverty and vicious online hatred I kept hearing about. Thankfully, this whole process has actually turned out to be great all around. You’re make this community fun and interesting to interact with. This is an awesome job and I very much appreciate you in giving it to me.

New trailer released

Posted June 13th, 2015 by Tynan Sylvester

I’ve just released a new RimWorld trailer! The format is the same as the old one, but all the content has been updated to the new hotness. Enjoy.

RimWorld Alpha 11 – Sappers and Traps released

Posted June 10th, 2015 by Tynan Sylvester

It’s here! This update includes clever new AI strategies including sappers who blast and dig around your defences and raiders who burn crops. I’ve also added a number of incidents, including several long-term atmospheric conditions like volcanic winter and toxic fallout. There is also an array of new traps for players to use, dozens of other new features and hundreds of fixes and small improvements. A full change list is at the end of this post. If you wish, you can also read my day-to-day work log here.

If you own the game, you can get the new version by re-downloading from the link you used before (it is a permanent link and always has the newest version). You should also get an update email from us. Anyone still having trouble should start at this thread. There may be a delay of some hours before your download count resets or your email arrives.

Also note that this build will not load old savegames or old worlds, so please don’t try to load these in the new version. They’ll probably just crash the game.

Change list:


  • Added new raid type: sappers.
  • Sappers attempt to dig or blast their way around your hardest defensive point. The circumvent ‘killbox’-like strategies.
  • Enemies now flee things that are about to explode
  • Enemies remember trap positions that their faction has encountered before, and avoid them.
  • Raiders opportunistically ignite crops on fire.
  • Pawns can now do ‘job override’ checks to see if a new job should start before ending their current job. These are now used liberally to have pawns respond faster and more intelligently to changing conditions (especially in combat).
  • Pawns check for job override when taking damage. It will no longer be possible to bug out the centipede enemy and kill him at close range while he tries to take a firing position.
  • Enemies no longer take unpowered player turrets as primary targets.
  • Pawns choose sky-gaze, wander, eating and other positions by traversing the region graphic instead of by random coordinate scattering, which solves problems with them taking long paths around long walls.


  • Added deadfall trap: A simple rearmable trap that falls on enemies and damages them.
  • Added IED trap: An artillery shell connected to a trigger that detonates after a short delay.
  • Added incendiary IED trap: Like IED, but sets fires.

New incidents

  • New incident: Toxic fallout. A toxic cloud that lasts for days or weeks. It kills plants, rots food, and slowly poisons people outside. Toxic buildup in characters leads to vomiting, dementia, and eventually death.
  • New incident: Volcanic winter. Lasts weeks or months and significantly reduces temperatures and light levels, leading to poorer harvests.
  • New incident: Manhunter pack. A pack of deadly wargs arrives and stalks the local area for a while before moving on. Fight them or hide inside from them.
  • New incident: Chased refugee. A refugee radios and offers to join the colony if you’ll fight the raiders on his tail.
  • New incident: Psychic soothe. The opposite of a psychic drone.

Allowed areas

  • Assign colonists to allowed areas.
  • Every item and location outside the allowed area is considered forbidden.

Storyteller changes

  • Storytellers will never entirely disallow events because of population.
  • Randy’s event chances are affected by population (somewhat).
  • Re-tuned storyteller population intent based on new output tables for smoother population gain with higher maximum and better recovery at small populations

Ice sheet

  • Ice sheet biome is now playable (though perhaps not survivable).


  • Added strip designator to reduce stripping micromanagement.
  • You can toggle allowing sowing in a growing zone.
  • Doors can be held open.
  • Door locking is now door forbidding (it’s clearer).
  • Added copy/paste functionality for storage zone/building settings.
  • World data now saves into map file to prevent game state confusion with multiple saves on one world.
  • Added new joy activity: build snowman.
  • You can now remove floors to reveal the terrain underneath.
  • You can now perform surgery on guests. Violating surgery will anger their faction.
  • Guests are smarter and no longer walk out of the colony bleeding.
  • Added new hairs donated by Shinzy.
  • Slave trader changed to pirate merchant, can still show up to buy slaves even when your population is high (though they may not carry any).
  • Hundreds more bugfixes, tuning changes, optimizations, and other small improvements.

Bug warning: Don’t change storytellers

Posted May 1st, 2015 by Tynan Sylvester

A bug has been discovered that will break storytellers if you change between Randy and Cassandra/Phoebe.

If you do this, the game will simply cease sending events. No traders, no raids, nothing.

You can still change difficulties. You can also still change between Cassandra and Phoebe. Just don’t change to or from Randy.

Sorry about that. Will be fixed in next build.

Hotfixed to Alpha10e (updated to Alpha10f)

Posted April 22nd, 2015 by Tynan Sylvester

This hotfix was broke for the first few hours of its release, when it was called Alpha10e. If you got it during that time, please re-download the fixed Alpha10f. The fix solves an issue in Alpha10e where rain would never put out fires, leading to the whole map burning down.

This small hotfix cleans up some minor issues that remained in Alpha10d.

To update, just use your existing download link from your last update email – it always gives the latest version. Save games from Alpha 10 will still work. To install, delete your old install directory and unzip the new Alpha 10f files to a clean empty folder (your save data is not stored in the install directory).


  • Reworked apparel optimization AI. Now they very much prefer wearing anything over wearing nothing (so they don’t walk around naked with clothes on the floor), and have a lower threshold of quality difference to replace apparel.
  • Optimized fire significantly so large fires won’t slow down your computer as much.
  • Some very minor fixes.

Hotfixed to Alpha10d

Posted April 20th, 2015 by Tynan Sylvester

So I got to have that special moment where you’re looking at some game code and you realize that the game you shipped last week to 75,000 people is totally horribly broken in subtle but game-destroying ways. This is the hotfix to the problem I found and others. Up to now, Alpha 10 has been basically broken.

There were a number of issues but the biggest one was probably the broken enemy fleeing and recruitment code that made it way too hard to get new people.

Sorry about releasing a kind-of broken version. I’m thinking that for Alpha 11 I’ll start doing public unstable builds a week before the stable release. It’s getting really hard to catch all the bugs in the game as it becomes more complex and it takes longer to play.

To update, just use your existing download link; it always gives the latest version. Save games from Alpha 10 will still work. To install, delete your old install directory and unzip the new Alpha 10d files to a clean empty folder (your save data is not stored in the install directory).


  • Fixed and rebalanced prisoner recruiting: Prisoners no longer get cabin fever and no longer have a joy need (until we get support for proper prison complexes). They can be recruited at any mood over 35% (though the chance may be very low).
  • Fixed a units change bug that caused 40% of enemies to flee after taking one hit, and other enemies to never flee. Now the flee properly with individual health thresholds again.
  • Fixed PawnName parsing so pawns with apostrophes in their names will work.
  • Cleaned up and robustified the AI with regards to finding a space to stand next to medical beds. Abolished the “medical bed needs headspace” alert as it’s no longer needed.
  • Fixed a bug that caused colonists to get stuck switching apparel over and over given certain weather conditions and combinations of apparel (they were considering the needed warmth in relation to their own current apparel instead of in relation to their absolute naked needs).
  • Fixed a bug that would crash the UI if colonists hauled a sculpture or TV while the player was selecting an install location.
  • Fixed bug that caused pawns to sometimes teleport to the bottom left corner of the map.
  • Fixed the needs tab not displaying on animals if a human was never previously selected with the needs tab.
  • Fixed a bug that caused colonists to spaz out around the billiards table when they reached full joy instead of just ending the job.
  • Some minor storyteller tuning.
  • Some minor typo fixes in game text.