Thoughts on Coriolis: The Great Dark

Posted: 2024-04-03
Word Count: 1424
Tags: coriolis rpg year-zero-system

Table of Contents

Free League Publishing have a kickstarter for a new version of Coriolis entitled Coriolis: The Great Dark. The setting and the rules differ from Coriolis: The Third Horizon, with only a few scattered callbacks.

Free League has also said that their publishing and support of the original game will end. The Great Dark is essentially Coriolis 2.0, and understandably they don’t want to sell both old and new editions. They will announce an “open license for third party content” for both games shortly.

I have decidedly mixed feelings.

The End of the Third Horizon

The Kickstarter writes whiat might be an obituary for the Third Horizon.

Coriolis: The Great Dark is the next step in the Coriolis saga. The game was first developed in 2008 and later updated and revamped in 2016 (Swedish edition) and 2017 (English edition) with expanded setting and the award-winning Year Zero Engine as well as the massive campaign Mercy of the Icons which came into conclusion in 2023.

The previous iteration of the game was set in a Third Horizon far from the cradle of humanity, with a vast and teeming civilization spanning a multitude of star systems, and as many cultures.

Now, I’ve never played Coriolis: The Third Horizon. I’ve wanted to, ever since I read it, but I could never gather the right group of players. (Or the courage to tackle such a sprawling, non-Eurocentric setting.) Hearing now that this game I’ve wanted to run for a long time is now going out of print is frustrating. Hopefully Free League will continue to make the PDFs available on DriveThru RPG, if they’re going to allow third parties to continue to develop content for it.

(Also, I don’t own Mercy of the Icons trilogy, let alone played it. This is why I hate metaplot: it takes a setting that could develop in one of a nigh-infinite number of ways and drives it to a single, typically apocalyptic, conclusion.)

But I’m still going to play a Third Horizon game, someday. Maybe.

The Coming of the Lost Horizon

The Kickstarter text quoted above continues:

Coriolis: The Great Dark takes the mysteries that were unsolved in the old game and moves forward to a new, albeit more desolate Horizon – where they will be answered.

That’s nice, but how does the new game look?

The Setting

To summarize, during the Mercy of the Icons colony ships took off to escape a raging war, lured by the signal of what could be the Nadir, sister-ship to the Zenith, a generation ship that settled the Third Horizon long after the dominant human culture developed.

What the colony ships found, before the signal cut out, was a seemingly dead region of space, filled with mysterious alien ruins and no working portals. Developing a sort of “slipstream” drive that relied on huge and well-armored “greatships”, the colonists established a single city on an asteroid and sent expeditons to plumb the depths of the ruins. There they found alien life(?) forms and the Blight, a bizarre disease(?) that seems to warp reality itself.

The System

Reading through the playtest/quickstart document I noticed several differences from the previous Coriolis system:

These mechanics cleave more closely to the Year Zero Engine SRD, while solving some problems with the old mechanics:

A number of mechanics revolve around the Delve, the search for alien artifacts. Each Delve requires the group carry a sufficient amount of Supply – an abstraction for oxygen canisters, food, water, batteries, etc. – to complete the Delve and come back. Delves are rated on difficulty (0-3) and Markers (amount of Supply per person required, assuming all goes to plan). It’s almost like old school D&D (or Shadowdark) where you have to manage your resources, and when you’re in danger of running out it’s time to come back. Or die.

Most Delves are following the paths set by previous Delvers, but of course there are surprises: monsters in the dark, unexpected Blight, treacherous colleagues …

Choose Your Horizon

As I said at the top, I’m conflicted. I’d like to run at least a one-shot of the original Coriolis, but I’m also itching to run the adventure in the quick-start too.

Coriolis: The Third Horizon and Coriolis: The Great Dark differ not only in mechanics but in tone and setting. For all its flaws, C:TTH portrays a vibrant cluster of 36 stars with its own politics, religion, and culture. C:TGD on the other hand is a last lonely outpost of humanity struggling against cold equations and an inhuman Blight. TTH has rules for building your own ships and exploring populated planets; TGD (as I read it) has predefined “greatships” ferrying explorers from The Last City to dangerous alien ruins. The new book portrays a bleaker, darker cosmos, influenced by ALIEN, Death in Space, and Mork Borg, and I’m not sure how they’re going to flesh out a “horizon” that isn’t just a grim grind.

The new system, from what we can see, looks cleaner. I’d almost like to see the CTGD system ported to something like the CTTH setting.

So honestly I refuse to choose. I’ve pledged to the Coriolis: The Great Dark Kickstarter, enough for PDFs and hardcopies of both the main book and the introductory campaign. On the other hand, with Vaesen, Mutant Year Zero, and Forbidden Lands gathering dust on my shelf along with the original Coriolis, I’m wondering whether and to what extent I should invest in a bleak game of alien contagions, incomprehensible ruins, and lost ships.


Longtime readers (if any) may expect me to grind out a program detailing the dice probabilities for the new system for Coriolis: The Great Dark. In this case, though, I’ve already done it. Since all dice that show ones cannot be rerolled, I just have to extend the table to 12 (9 base dice, 3 gear dice) and take just the first two columns.

ndice Normal Push
1d 16.67% 27.78%
2d 30.56% 47.84%
3d 42.13% 62.33%
4d 51.77% 72.79%
5d 59.81% 80.35%
6d 66.51% 85.81%
7d 72.09% 89.75%
8d 76.74% 92.60%
9d 80.62% 94.65%
10d 83.85% 96.14%
11d 86.54% 97.21%
12d 88.78% 97.99%

  1. I do wish they change the name, though: it suggests courage or even love. I’m not sure what would be better, though. Sanity? Stability? ↩︎