Game Mechanics

Delta Green is about cover-ups, insanity, and death. The world is a lie. Beneath it, things squirm, struggling to punch through and raze everything.

Once you see the outline beneath reality, it cannot be unseen.

Welcome to the truth.

That’s what the dice are for: to stand for an indifferent universe where fear, courage and hope matter less than an atom in an ocean of stars. Still, you fight. For your family, your friends, your way of life. You fight to live one more day.

Here’s how the game works.

Using Skills
Delta Green’s rules focus on skills. You decide what your Agent attempts to do; the Handler determines what skill to use. In a typical mission, Agents use many different skills.

Sometimes using a skill requires a roll of dice. The most important rule is this: The Handler determines if, when, and what you roll. If the Handler says a roll isn’t needed, the skill rating itself determines success or failure.

If the Handler tells you to roll a skill, it’s a skill test. The dice determine success or failure. Roll two ten-sided dice to get a number from 01 to 00 (1 to 100). Roll your skill test rating or lower to succeed. Rolling higher means failure.

If your Agent has a 0 in a skill, he or she can’t even attempt to use it. It requires specialized training or education that your Agent lacks.

Using a Stat
If your Agent tries to do something that anyone ought to be able to do—something that’s hard, but doesn’t require specific training like a skill—then the Handler might look to one of your Agent’s stats, for a stat test. A stat test is the relevant stat × 5. (So with STR 11, a STR test is 55%.)

Bonuses and Penalties
Having to make a skill test in the first place means there’s a substantial chance of failure. But if the odds are really against your Agent, the Handler might impose a penalty, down to a minimum chance of 1%. If the situation is a little more in your Agent’s favor, the Handler might allow a bonus, up to a maximum chance of 99%.

If a bonus or penalty applies, it’s usually +20%/−20% or rarely +40%/−40%.

Successes and Failures
On any skill or stat test, there are only four possible outcomes. From best to worst they are: Critical Success, Success, Failure, and Fumble. Ordinary success and failure are most common. Critical successes and fumbles represent exceptionally good or terrible outcomes.

Critical Success
A critical success is a roll of 01 or any success where the dice match. So if your Agent’s skill is 50%, you achieve a critical success with a roll of 01, 11, 22, 33, or 44. A critical success automatically succeeds, and exceeds expectations. A critical is twice as good as an ordinary success. What twice as good means must be taken in context of the action. In combat, a critical success means double damage, but during an investigation, it might mean the action takes half as long.

Success
A success is a roll equal to or less than the test chance. With a success, your Agent accomplishes what he or she set out to achieve.

Failure
A failure is a roll that’s higher than the test chance. Sometimes that means your Agent suffers harm. There may be times when a failed roll means an Agent achieves what he or she wanted—but it comes with an unpleasant complication. The Handler always decides whether that’s the case and what the cost will be. For a few possibilities, see the effects of fumbling a roll.

Fumble
A fumble is a roll of 00 (100) or any failure where the dice match. So if your Agent’s skill is 50%, you fumble on a roll of 55, 66, 77, 88, 99, or 00. A fumbled roll fails, no matter how high your Agent’s chance of success, and has additional, catastrophic consequences.

In a car chase, a fumble might mean your Agent crashes. In a gunfight, a weapon might jam or one might accidentally shoot oneself. The exact complications are up to the Handler

The Luck Roll
Events often come down to pure chance. Are the neighbors home when your Agent breaks down the apartment door? Does the stolen car have a first aid kit in the trunk? When an unexpected burst of fire tears down the door, does a bullet find you? If the Handler calls for a Luck roll, there’s a 50% chance that things go your Agent’s way. It doesn’t depend on psychic talent or your Agent’s connection with the cosmos or anything else. Just roll the dice. With a critical success or a fumble, your Agent’s luck is extra good or bad.