These are the game mechanics used to play and run a game of Rainworld at the table.

The basic mechanic

Rainworld uses two 10-sided dice, with their results added together (2d10) to find out whether characters succeed at the things they attempt. (Certain rules use other dice: usually six-sided dice — d6s, or four-sided dice — d4s.)

A check is 2d10 + skill + any bonuses − any penalties; any result over 10 is a success; 10 or less is a failure.

When you roll doubles, that’s a critical result — Control will decide what extra effect the critical has on your success or failure.

An untrained check uses a skill that the character has no ranks in. Untrained checks take a -2 penalty.

Sometimes, a player’s character will pit their skills directly against an antagonist with skills of their own, in a versus check — your Stealth versus someone’s Observation, for example, to sneak past them. The antagonist will make a check; instead of aiming for the usual result > 10, the player’s check needs a result better than the antagonist’s to succeed.

If you want some kind of extra effect, you can bargain with Control before making the check. This is called a Raise, because it raises the difficulty of the check — Raise 1 is a -1 penalty, Raise 2 is -2, etc. Control will decide how much you need to Raise for the effect you want (and if you ask for too much, they can just say no).

Some equipment increases a character’s effective ranks in a particular quirk; in general, only one piece of equipment can supplement a given quirk for any particular check. (For example, if a character has a helmet with integrated smart scope and a gun with an aim-assist device fitted, and both give effective ranks in Marksman, the character has to choose which of them to benefit from.)

Space and Time

As in many RPGs, things happen in Rainworld on two different timescales — Continuous and Granular Time.

For much of the game, precise times and distances, and the exact order of things happening don't matter. You just give Control and the other players a good enough idea of what your character does, and it all goes fine. Other times, though, it matters — do you shoot first, or does your opponent? Are you close enough to get to cover before the grenade goes off?

When it matters, the game enters Granular Time, and it stays there until it stops mattering. When Granular Time starts, everyone involved rolls 2d10 + Tactical Awareness; the number they get is their Initiative for this period of Granular Time. (To tie-break equal Initiatives, the character with the highest Tactical Awareness goes first; if still equal, Control determines randomly.)

Granular Time advances in rounds. Each round has three phases — Fast, Go, and Slow, which happen in that order. A phase isn’t a set length of time; like a comic book panel, it feels instant, but takes up just enough time for everything in it to happen. By default, everyone gets to act once per round, during the Go Phase. However, there are a number of conditions alter that:

  • Surprised means that the character can’t take any actions this round. The Suprised condition automatically ends at the end of the round
  • Fast Start means the character acts in the Fast Phase
  • Slow Start means the character acts in the Slow Phase
  • Fast and Slow Start are mutually exclusive. If a character somehow acquires both conditions, their default action resets to the Go phase
  • Go-Again+ means the character gets an extra action, in the fastest phase that they don’t already act in
  • Go-Again means the character gets an extra action, in the slowest phase that they don’t already act in
  • (This means that, by default, characters go once in a round, and others taking full advantage of the rules may go up to three times — both before and after them)

Within each phase, everyone able to act in it goes in Initiative order, highest first.

It’s possible for Granular Time to be triggered by an ambush, or some situation where some or all parties are otherwise caught unaware. Control will call for an appropriate check — ambusher Stealth versus target Observation, for example. Anyone caught unaware who fails the check gains the Surprised condition.

Rainworld recommends keeping track of everyone’s positions during Granular Time on some kind of grid — graph paper, an RPG battle map, or terrain tiles. RPG products customarily use 1 inch squares; for Rainworld purposes, each such square represents 1m2. (That means that the default MV 5 = 5 squares of movement per phase.) This isn't always practical, and not everyone likes battle maps; you can (and the authors have) run Rainworld perfectly successfully without. (You might, in that case, need to selectively ignore hard-to-adjudicate rules such as firearm Increments.)


Whenever a character acts, they get to do any combination, including none or all, of: move, one Basic Activity, one Adjunct Activity, and any number of Free Activities, in any order they like. The character’s movement can be split up around their activities however they like, but the total movement during each round (not phase) can’t exceed their MV.

Adjunct Activities are only available when specifically granted to a character — by a quirk, equipment, etc.

Free Activities are anything that Control agrees don’t amount to the time and effort of a Basic Activity — shouting a warcry, emoting over a Ganzfeld telepathic link, dropping something your character is holding, etc.

Basic Activities include:

  • attacking someone or something
  • activating a Ganzfeld Flow technique
  • most other skill checks (adjudicated by Control where necessary)
  • aiming a firearm
  • using or interacting with an object (including drawing, holstering or reloading a weapon)
  • defensive manoeuvring (until the defensive character next acts, opponents take the character’s Gymnastics skill as a penalty when attacking them)
  • sprinting (until the end of the current round, the character’s effective MV increases by the value of their MV stat)
  • suspending an activity

A suspended activity consists of a specific Basic Activity and a specific trigger condition. Instead of acting immediately, the character waits to see if the trigger condition happens — if it does, that’s when the character performs the suspended activity. (For example, you can suspend an attack in case enemy reinforcements come through the door.) In every subsequent phase when the character has an action, they can choose to keep waiting for the trigger, or to lose the suspended activity and do something else — they can’t do something else and keep waiting.


Attacking usually uses one of the Melée Weapons, Firearms or Martial Arts skills — all unarmed attacks, including untrained punching, kicking, etc. use Martial Arts. (Throw is sometimes an attack skill. A grenade, say, usually isn’t an attack — the point is to get it near the target, and that’s not affected by the target’s defensive manoeuvring. Throwing a brick at their head, though, is.)

A called shot is a Raise to attack a specific part of the target, varying depending on the difficulty (shooting someone in the eye is harder than just in the head, for example).

Unarmed strikes inflict 1 box of damage. Untrained Martial Arts attacks inflict stun, or injury on a critical success. Trained Martial Arts attacks can choose whether to inflict stun or injury.

A weapon may specify a minimum PHYS. Characters whose PHYS stat is below the requirement take the difference as a penalty to their attack.

A split attack means the character attacks with both hands, simultaneously but separately. (One Plasmadze in either hand, for example — not a single two-handed Plasmax.) The split attack uses a separate skill check for each hand. Most characters have a dominant and an off hand; attacks with their off hand take a -3 penalty. If the attacks target two different opponents, both checks take an additional -3 penalty for the difficulty in correctly coordinating that.

Aiming can be done for any number of phases before firing a gun. Unaimed shots take a -3 penalty. Taking any Basic Activity other than firing or continuing to aim abandons the aiming, resetting your shots to unaimed.

Firearms have an Increment, representing their accuracy at range. There are bonuses or penalties to a Firearms check with the weapon, depending how far the character is shooting:

  • firing at someone attacking you in melée: -3, doubled to -6 for firearms longer than a pistol
  • when not in melée, point blank range (less than 5m): +3
  • outside point blank range, up to the first Increment for the firearm: no modifier
  • at long range (one or more Increments): a penalty equal to the square of the number of full Increments the shot crosses (i.e. -1 for targets beyond the first Increment; -4 for targets beyond the second; -9 for targets beyond the third, etc.)
  • Firearms have one or more firing modes: single, burst, and auto. Single fires a single round per action. Burst-fire weapons specify how many rounds they fire per burst (i.e. burst 3 is a 3-round burst). Auto denotes a fully-automatic weapon, capable of firing any number of shots — up to emptying the weapon — as an action.

    Burst and auto fire work differently to normal attacks. Instead of a Firearms check, roll a pool of d10s, one die for each bullet fired; every die that rolls equal to or over the success threshold represents a bullet hitting a target. If directing burst or auto fire at a single target:

    • The default threshold is 6
    • Each rank in the Autofire quirk (see p) reduces the threshold by 1 (to a minimum of 2)
    • Each full range Increment increases the threshold by 1

    Instead of directing burst or auto fire at a specific target, the character can simply spray an area with bullets:

    • The default threshold is 10
    • The Autofire quirk does not apply — spraying is too inherently inaccurate
    • Each full range Increment increases the threshold by 1
    If you roll any hits while spraying, Control will determine which targets take the bullets.

    Melée weapons and ammunition types have a damage rating (DMG). Armour has a stopping power (STOP). On a successful attack, the weapon does its DMG in injury to an unarmoured target. Armour subtracts its STOP from incoming DMG (to a minimum of 0) — however, if the weapon or ammo has armour penetration (AP), it reduces the armour’s effective STOP by its AP (to a minimum of 0).

    i.e. actual damage taken = DMG—(STOP—AP), where each subtracted value can't fall below 0

    Shotguns firing shot pellets have their DMG reduced by the number of full Increments crossed.

    Failed attacks with some weapons, such as grenades, represent inaccurate placement. Control will determine the direction and distance the attack is offset from its intended target.

    Explosions, such as from grenades, have an epicentre radius and effect, and a falloff effect. When the explosion detonates, characters within the epicentre radius suffer the epicentre effect. Characters outside the epicentre radius, but within 2×the epicentre radius, suffer the falloff effect.

    Throwing objects doesn’t use Increments in the way firearms do. Instead, the distance (in m) which characters can throw things without penalty is the lowest of their PHYS or CON; for each 1m beyond that they attempt to land it, they take an additional -2 penalty to the skill check.

    Non-Combat Ways To Die

    Characters can be injured by falling — 1d4 boxes of injury for each full 5m they fall. (That makes a fall of 50m unconditionally lethal.)

    Characters can hold their breath when deprived of breathable air for PHYS×30s; following that, or otherwise deprived of oxygen, characters will take 1 box of stun per round — then, once unconscious, 1 box of injury per round.

    Characters who are on fire take 1d4 boxes of injury per round.

    Mental Health

    Characters’ mental health can be damaged, as well as their physical bodies. This is rarely as simple as physical damage — nobody can buy a gun that fires mental trauma. Generally, characters will gain psychological damage by failing Endurance checks under stressful, shocking or horrifying circumstances.


    Click is a player-facing resource which represents things just working out for their character. You start each game session with a pool of Click equal to your character's Click stat; you can spend one to:

    • immediately reroll one failed check
    • buy some kind of extra effect if your next roll succeeds (subject to Control’s usual approval) without a Raise
    • discover a single handy-but-plausible thing tucked in one of your character’s pockets — a pack of cigarettes to bribe a guy with, chewing gum, a spare pen, your lucky bullet
    • Stabilise your dying character

    In addition to the standard uses of Click, all human characters can use their social privilege to spend a point of Click for one of these benefits:

    • +3 bonus to an Interact or Bureaucracy check with a fellow human
    • +3 bonus to an Aggro roll with a nonhuman

    Damage and Healing

    Each character has two 10-box status tracks, Body and Mind. The Body track represents the character’s "hit points" or physical health; the Mind track their mental integrity in the face of trauma, horror and terror. (Ganzfeld characters have a third, the Reality track, representing damage to their connection with objective reality done by their psionic powers.)


    There are two types of physical insult your character may receive: injury and stun. Injury requires medical attention; stun can be shrugged off with little more than rest.

    Injury fills the Body track left-to-right, marked off with /; as the Body track fills with injury, characters take increasing penalties to all their actions (at their second, fourth, sixth and eighth box of injury, marked along the bottom of the track on the character sheet).

    If the Body track completely fills with injury, the character is dying. Medical attention can stabilise them in this state; without hit point restoration or stabilisation, they die within PHYS÷2 minutes. Reaching the dying state and surviving gains the character 1 trauma on the Mind track.

    Stun fills the Body track right-to-left, marked off with \; if the Body track fills with stun, or if stun and injury overlap somewhere in the middle of it (a / and a \ form an X), the character is incapacitated — knocked unconscious or completely immobilised.

    An overnight period of reasonable rest and self-care will remove all stun. A period of downtime ranging from days to months is necessary to naturally heal injury. (Paying for medical treatment shortens the length of time necessary to heal — negotiate specifics with Control.)


    Similarly to the Body track, there are two types of mental strain your character may undergo: trauma and shock. Trauma is deeply affecting and long-lasting; shocks are transient events. Trauma fills the Mind track left-to-right (/), and shock fills the Mind track from right-to-left (\).

    If the Mind track fills with shock, or shock and trauma overlap (a / and a \ form an X), the character has some kind of uncontrollable episode — violent rage, terrified escape, unresponsive fugue, or another symptom of their psychological damage. This will remove all of their current shock and replace it with +1 trauma.

    If the Mind track fills with trauma, the character’s mental health permanently breaks down. They are unfit for further duty, and will be discharged from S4G at the earliest possibility; early contract termination fees may apply. (Although the character may still occupy the game world as an NPC, like dying, this permanently removes the character from play.)

    An overnight period of reasonable rest and self-care will remove all shock. Long-term problems can be addressed with downtime mental health treatment, possible medication, and/or 5XP per point of trauma removed.

    Ganzfeld Reality damage

    See the Ganzfeld section.


    Each individual substance that a character is dosed with may be addictive, adding its own substance-specific Addiction status track to your character's information. The number of boxes in its track is listed in the substance description in the Gear section.

    Similarly to the Body and Mind tracks, each addiction track fills right-to-left with doses taken (\), and left-to- right with points of addiction (/). When it fills with doses or overlaps (X), it is emptied of doses and gains a box of addiction.

    When the addiction status track for a substance is filled with points of addiction, the character is addicted to that substance. They remain addicted unless they remove all boxes of addiction from the status track.

    An addictive substance may list effects which are continuously experienced by characters addicted to it. These effects stop only when the character ends their addiction.

    Addictive substances may specify a withdrawal duration and effects; the addicted character starts experiencing the withdrawal effects when their last dose was more than the withdrawal duration ago. Withdrawal effects stop when the character has their next dose, or ends their addiction.

    Recovery from addiction can be done with assistance from a Ganzfeld who knows certain Flow techniques; by using quitting-aid pharmaceuticals; or by negotiating downtime rehab with Control and spending 1XP per box of addiction removed.