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Co-op Case Study: Sub Terra

Our Kickstarter for Meeples Together ends this week, but we’ll be continuing to publish new case studies supplementing the book in the weeks and months to come. (We’ve got more than 50 additional case studies drafted, plus another handful planned.) Today’s talks about Sub Terra, one of the big co-op Kickstarters in recent years, and one that turned out to be quite a good game too!

This article has been crossposted from the Meeples Together blog, which focuses exclusively on cooperative game design.

Publisher: Inside the Box (2017)
Cooperative Style: True Co-op
Play Style: Action, Tile Laying


Whoops! You fell in a cave! And your flashlight batteries are going to run out! You and your fellows thus have a limited amount of time to explore the caverns by laying tiles, trying to find the exit. However, floods, gas, and quakes all make those tiles more dangerous … and then there are the monsters hunting you in the dark!

Challenge System

As in most co-ops, the challenge system in Sub Terra is triggered by the draw of a card, which reveals a new hazard. However, Sub Terra’s challenges have a unique twist: though a few such as “Tremor” and “Out of Time” have global effects, others such as “Cave-In”, “Flood”, and “Gas” are linked to specific tiles. This creates a very elegant interdependence between the co-op system and the game’s main (tile-laying) mechanic — something that any co-op could benefit from.

This is supplemented by a combat-threat system that’s much more typical, but that still has interesting complexities: monsters are activated by card draws; every turn, they then move toward the nearest player. The very constrained passages of Sub Terra turn this into a simple simulation where the players can carefully control the movements of the monsters, much as is possible with the slave catchers of Freedom: The Underground Railroad (2012). Combining this sort of controllable threat with something more random, like a card draw, supports both player agency and the surprise of an unexpected occurrence: in Sub Terra, not only do you not know when new threats will appear, but there’s also a slight chance that they’ll move double speed each turn.

Sub Terra contains one other challenge element is of note: it essentially contains two timers. If players get to the bottom of the tile deck, that’s a good timer, because they find the exit, but if they get to the bottom of the hazard deck, that’s a bad timer, because their flashlights go out. This struggle between two different clocks is quite unique in co-op play.

Challenge System Elements: Turn Activation; Arbitrary & Simulation Triggers; Sequential Cascade; Decay; Timer & End-game Goal; Environmental Consequences; and Combat & Skill Threats.

Cooperative System

The cooperation in Sub Terra is entirely strategic, with different players taking on different tasks, but the game is rather uniquely designed so that this strategic play is both required and deleterious! The strategic play is enforced by the need to reach the bottom of the tile deck: players must split up to explore enough tiles over the course of the game. It’s contradicted by the fact that players must be together at the end of the game in order to get out of the caves: if they’ve gotten too far apart, some will be stranded and everyone may lose! The back and forth between strategic exploration and possibly wasteful congregation is another strong tension in the games; other co-ops could probably benefit from Sub Terra’s idea of simultaneously rewarding and punishing strategic play<<IDEA>>.

Players can also work together to clear cave-ins, to heal fallen comrades, or to use their specific advantages for the good of the group. There’s a wide variety of ways that players can cooperatively interact, which creates interesting gameplay.

Adventure System

Sub Terra is on the fringe of adventure gameplay, with a few elements of particular note.

The most important adventure elements are the characters, which each have special abilities that are specialized enough that they will push players in specific gameplay directions. There’s also a simple skill-check system: a player rolls a die and tries to get 4 or more.

None of this is particularly complex, nor are there any surprises, but these simple adventure-game systems show their important to cooperative games.

Expansions & Variants

Sub Terra was Kickstarted with a huge variety of add-ons and variants. A lot of them were cosmetic, but there were also three small expansions: Annihilation (2017), Extraction (2017), and Investigation (2017). Each introduces a new player character and also features some slight new rules for play.

Final Thoughts

Sub Terra’s greatest strength is its integration of random tile-laying play with cooperative gaming. Though there are certainly other games that feature tiles, such as Mansions of Madness (2011, 2016) and Star Trek: Expeditions (2011), most haven’t managed to capture the fun and excitement of tile draws. Betrayal at House on the Hill (2004) and its various spin-offs was probably the only major release to really exemplify the joy of exploration that tile laying can create, and Sub Terra follows right in those footsteps. It also takes a step forward by truly intertwining the tile-laying and the challenge play, making them into a cohesive whole.

Other elements of the game are more mundane from a design perspective, but the result is nonetheless exciting, tense, and fun, which is all you can ask for.

Tim Pinder

Although he’d previously self-published Draftica (2015), Sub Terra (2017) marks Tim Pinder’s first fully professional game design.

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The original article can be found on the great Mechanics & Meeples