Brainstorming: Zombie Apocalypse for Cortex Plus Action

I’ve been thinking about this for a long time: how would you run a Zombie Apocalypse in the Cortex Plus family of games? Every time it comes up, the ineffable Cam Banks — who may or may not have had something to do with Cortex Plus being awesomesauce — says, “use Drama!” and every time my response is, “I’m an idiot, so no!” and really I don’t have a good reason.

Actually, the real answer is: “I want to run some action-heavy one-shots or a very short, high-octane, running-away-from-zombies-as-a-team” scenario. I don’t have time for the (admittedly awesome) long-term benefits of running a more Walking Dead-style campaign with antagonistic player characters, so basically, I’d lose out on the intricacies that I like most about Cortex Plus Drama. Why waste that?

Below is my initial brainstorm for Zombie Apocalypse roleplaying in the Cortex Plus Action system, specifically the Firefly Roleplaying Game flavor of Action. The core idea here is that the players are Survivors who have to run “missions” to get supplies, save people, or otherwise gain some short-term resource/benefit. Being that they come from all walks of life (before the apocalypse), they will basically bungle through these missions, narrowly escaping zombie bites, and likely getting into tense negotiations (or running gun-battles) with antagonistic survivors, and occasionally face the elements. The threat of the zombie hordes growing and growing builds in the background of the story, but in a way that’s highly visible during play, and thus (hopefully) very, very tense.

Zombe Apocalypse: Preparation Level Genius

They call them “walkers” for a reason…


Most are mooks using the Ganging Up rules. Badly damaged zombies (crawlers, sewer zombies) are d6, typical Romero-style slow zombies (but still with most/all limbs and fully ambulatory; slouchers, fused, thinkers) are d8, and fast-attack zombies are d10. Juggernauts or large fused zombies might be d12. Here’s a brief list of a bunch of different types of zombies, just to get the gears turning. Most of this is inspired by Dead Reign, Outbreak: Undead, and All Flesh Must Be Eaten.

  • Crawlers are zombies featuring significant damage to their body, which impairs their ability to move around.
  • Slouchers are the typical, Romero-style slow-moving walking dead.
  • Runners, or fast-attack zombies, are the guys from the remake of Dawn of the Dead, and so many other modern zombie movies.
  • Fused zombies are multiple individual zombies that have somehow become bound together, whether due to melting from fire damage, significant chemical burns or exposure, or perhaps supernatural means.
  • Rotters or sewer zombies might be slouchers or other types of zombies that have somehow become even more disgusting than typical zombies, perhaps through infestation of insects or parasites, or by being submerged in toxic chemicals, substances, or maybe even sewage.
  • Juggernauts are zombies that are especially large or strong. Imagine the biggest, baddest linebacker turned into a zombie. Or a 1,000+ pound  person that was a shut-in during life, but through the magic of undead revivification, came back as a fully mobile flesh-eater.
  • Walking graves are masses of zombies buried together — perhaps in a mass grave — and when they rose, they somehow got stuck together in earth, clay, or mud, and now are a huge mound of gnashing teeth and flailing limbs. Rarely are they mobile, but when they are, it’s probably not as a mook…

Non-mook zombies are likely to just be Minor GMCs (3-6 traits, usually rated d4 to d8, with only the rare d10 or even rarer d12). Likely traits will include whether the zombie is disabled, slow, or fast-attack. Or, rarely, some kind of juggernaut/mutant thingy (d10 or d12, usually). For example:

SCREAMER Variant sloucher (sloucher d8, screams are distracting d6, lunge d10, not that sneaky d4).

If zombies are on-screen and the quarters are cramped, it’s going to be High Stakes rolls all the way. Any time there’s plenty of escape routes, lots of open ground, and/or the party has taken extra precautions to know the area (usually in the form of overcoming previous challenges to recon an area or draw off zombies), then it’s not likely to be High Stakes…unless things go really sour.

As you’ll see below, I have some thoughts on making High Stakes rolls and/or conflict with zombies of any kind a bit more dangerous.

Viral Pool

The Viral Pool is a pool of difficulty dice, usable only on rolls by zombies. Under most circumstances, the session begins with the Viral Pool starting at d4. It is stepped up or stepped back per the rules in the following sections.

The GM can start the Viral Pool at a higher value if they feel an area has a high zombie population, but this should be used sparingly, as it is ridiculously easy to increase the Viral Pool throughout a session, and is a huge part of the tension of the game.

When the Viral Pool increases past d12, simply add a second die, starting it at d4. If the second die gets stepped up past d12, add a third die starting at d4, and so on. The Viral Pool never drops below a single d4, but it does not have a maximum, much to the chagrin of Survivors everywhere.

Increasing the Viral Pool

The Viral Pool increases…

  • Over Time: Step up 1/scene starting with the second Scene of a game session. This can be slowed if the GM feels the area has a low zombie population.
  • From Loud Noises: If the Survivors use loud devices (most gas-powered vehicles and tools, guns, radios), issue loud commands or react loudly (shouting, screaming), or carry out any other action that causes loud noise, they may borrow a single die from the Viral Pool for their action. Afterwards, step up the die and return it to the Viral Pool.
  • When Zombies Moan: If zombies get a chance to moan, they may take an action to roll and — if successful — step up the Viral Pool 1/scene.

I’m sure there must be some other ideas out there on this. I don’t want the Viral Pool to skyrocket every five seconds, but it should be scary.

As an aside, re-read that …From Loud Noises entry again. That’s why the Viral Pool is intense: it’s sitting there in front of the players, growing and growing. Not only that, but they can even make use of it…at the expense of watching it grow even more. A real jerk of a GM could not explain the Viral Pool and just offer those dice to the players from time to time. That’s just mean.

Decreasing the Viral Pool

The Viral Pool can be decreased…

  • When Survivors Keep Quiet: If the Survivors use stealth or take other actions to remain invisible to zombies (step down 1/scene).
  • When Survivors Stay Hidden: If the party fortifies a position so that zombies can’t sense them for the duration of an entire scene (step down 1/scene).

There might be some other ways to decrease the Viral Pool, like taking some sort of action(s) to just hose down an area with fire or lead or something, but I’m not sure how to really simulate this in a short, fast-paced scenario, or if it even needs to be addressed.

Timetable of Danger

The Timetable of Danger explains what happens when the Viral Pool is stepped up.

Random Encounters

Every time the Viral Pool is stepped up, a number of zombies equal to the roll of the Viral Pool show up at long range (see below). These zombies are always Slouchers d6, unless the scenario says otherwise. (For variety — and a modicum of balance — the use of weaker or stronger zombies in random encounters should alter the number that appear, generally reducing it to the roll of the highest die in the Viral Pool for weak zombies or the roll of the lowest die for stronger zombies.)

Long Range

Long Range is indeed meant to be a somewhat nebulous phrase, but it generally means: close enough for the PCs to notice (unless they are distracted by a tense situation, such as combat, and likely also have an obstructed field of view), but not close enough for zombies to appear on top of them. This varies based on the terrain, but basically should be:

*A block or two away, the PCs see zombies emerge from alleys and side streets.
*If the PCs are in a house, they begin hearing the sounds of zombies moaning on the same block.
*If the PCs are in a fairly large structure (bigger than a house), they may hear zombies knocking at the doors/windows to the outside.
*If the PCs are in a very large structure (a hospital), they hear the sounds of zombies moving about on the next floor (above and/or below), or maybe distantly down a long hallway.


Any time a die in the Viral Pool is stepped up to d12, a new Complication is added to the PCs (always starting at d6), or an existing one caused by previous instances of this occurrence is stepped up. Note that each has special rules outside of a typical Complication. Roll 1d6 to determine what the Complication is, or choose the one that makes the most sense:

  1. Random Encounter! No actual Complication is created; this result simply triggers a Random Encounter roll, as explained above. (As an aside, I’m not sure if this should be in addition to the Random Encounter triggered by the Viral Pool die stepping up in the first place, or if the d12 result on the Timetable of Danger should be independent of that.)
  2. Food Jeopardized: Food supplies either on the Survivors or at their safe haven are contaminated, spoiled, damaged, or lost. Once this is stepped up past d12, no Survivors are Taken Out, but instead they are out of food until they undertake a mission to scrounge some up.
  3. Water Jeopardized: As for Food Jeopardized, but relates to water supplies.
  4. Supplies Jeopardized: As for Food Jeopardized, but relates to scrounged supplies on the Survivors or stored supplies at their safe haven. This might include medical equipment and bandages, gasoline, batteries, towels, bedding, and so on. If nothing else makes sense, simply use the Gear Jeopardized result.
  5. Gear Jeopardized: As for Food Jeopardized, but relates to gear currently on the Survivors. The Players choose a single important piece of gear — medical equipment, flashlights, climbing gear, body armor, weapons, clothing — and that is the item in danger of being lost. Once this is stepped up past d12, no Survivors are Taken Out, but that piece of gear becomes useless until fixed (if it can be fixed, based on the situation).
  6. Low on Ammo: The Survivors are running low on ammo, or if their weapons don’t use ammo, the weapons themselves are beginning to show the signs of significant wear and tear. Once this is stepped up past d12, no Survivors are Taken Out, but their weapons become useless until fixed (if they can be fixed, based on the situation). This affects most or all weapons equally.

There are a lot of other possible options for Alerts. You could combine a few of the above options (Food/Water Jeopardized: roll 1d6, 1-3 Food or 4-6 Water) and thus open the 1d6 roll to a few more options, such as Friendlies do something stupid (an Extra dies), Innocent person needs rescuing, or Antagonistic survivors appear on the scene. You could just add a couple of these options to the Random Encounters option (#1 on the 1d6 roll) and thus tailor what random encounters really means, and not having it always be zombies. You could just jumble all this stuff together onto one table and roll 1d8, 1d10, or 1d12…however many options you’ve got!

I’m just not sure what works best, there, or if it’s a good idea to just fully develop like 2-3 different versions of this table and then choose. Hmmm.

When the Zombie Apocalypse comes gamers be like...

Am I the only gamer who realizes I’d be dead before this mattered?


Normally, Firefly/Cortex Plus Action doesn’t feature Stress. But, as Cryptico wrote a post about harsher trauma as a Stress track for a Cortex Plus zombie game, the possibilities of adding just one or two very specific Stress tracks could have some fun — and most importantly, meaningful — consequences:

What I did was use stresses like Drama but include the rule that if you get stressed out you can die or take or step up trauma and a tag to it but you get some narrative power to survive the situation. If your trauma goes past D12 then you die, go insane or are otherwise out of the story. This adds an element of disempowerment while showing your characters going through the trauma conga line. Now the focus of my hack is on the horror part of it while conflict between characters will have a prominent point it’s not necessarily the main focus.

The trauma die might look like:
D4: I have developed a phobia against the walkers.
D6: Lost my hand saving my friends
D8: Broken hearted over the betrayal of my lover

I’m considering an Infected Stress track, so that High Stakes conflict against Zombies has its own little counter that can be started and works similar to Cryptico’s idea — only physical rather than mental — where it’s less about morale/horror and more about how close a character gets to becoming a zombie. You could amputate or do other things (blood transfusion?) to lower it, or you could let it go untreated and once you pass d12…it’s ZOMBIE TIME! Maybe even having such a Stress track regardless of High Stakes rolling might make zombie encounters feel unique. Dunno.

Big Damn Hero Dice

Change the name to Headshot Dice. ‘Nuff said!


Well, I don’t have a conclusion, honestly. There’s a lot to think about, but so far, this is the clearest expression yet of what I’d like to achieve, and doesn’t really add any complexity on the player side, unless we start adding those Stress tracks.

Any comments, questions, or suggestions would be much appreciated! And maybe, someday, once I run this stuff, I can work on a bigger, more badass take that gives the Cortex Plus Drama system some love, so that Cam doesn’t have to keep shaking his head at me!

(I jest, Cam, if you ever come across this!)

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neuronphaser is an editor, eCommerce consultant, web producer, and analyst living in sunny Hollywood, CA. He's been playing tabletop RPGs of all kinds since 1985.

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