Project Name: Open PvE Card System (OPCS)

License: Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) Source: Game in the Brain

I. Mission and Vision

The Problem Statement

The modern Collectible Card Game (CCG) industry is built on a model of exclusion and artificial scarcity. It is intensely capitalized, designed primarily to extract continuous revenue from players through "Chase Cards," randomized booster packs, and intentional power creep. To stay competitive, players must perpetually buy the newest sets as older investments are rotated out. This creates a barrier to entry where the size of a player's wallet often dictates their capacity to win, rather than their strategic acumen or creativity.

The Solution: An Open Gaming PvE System

We propose an Open Gaming PvE CCG—a cooperative, Player vs. Environment card game where the "opponent" is an automated deck and the rules are open-source.

De-Commodified Power: Card scarcity does not determine power level. There are no "Ultra Rares." Power is balanced by in-game trade-offs, time-gating, and strategic design.
Proxy-Friendly: Anyone can print the cards. The game encourages "Proxy Decks." The value lies in the method of play and the social experience, not the speculative value of cardboard.
Collective Ownership: The rules, themes, and mechanics are transparent. A collective of players maintains the wiki, documenting tournament data and evolving the meta collaboratively.

The Target Ecosystem

The Players: Those exhausted by the "pay-to-win" grind. Players who want a GM-less, TTRPG-lite experience where they can gather with friends, build distinct character decks (Espionage, Combat, Politics, etc.), and solve puzzles together without a Dungeon Master.
The Artists: We create a marketplace where artists sell their art directly to players to use on card templates, rather than selling copyright to a corporation.
Small Publishers & Makers: A haven for creators of accessories—playmats, deck boxes, and tarot-sized sleeves—and local print shops that produce high-quality "Print on Demand" decks.
Digital Creators: An open API for app developers to build Deck Assistants, Rules Enforcement engines, and Generative AI tools that provide "flavor text" and narrative scaffolding during play.

II. The Core Mechanics

1. The Decks

The game uses Tarot-Sized Cards (70mm x 120mm) to maximize information density and legibility. Each player brings two decks:

The Asset Deck (AD): 30 Cards representing the Character’s Tools, Skills, Relationships, and Techniques. (The "AC").
The Environment Deck (ED): 30 Cards representing the Threats, Locations, and Circumstances the player wants to face. (The "EC"). This can be considered "Encounter Deck" as well.
Total Deck Size: 60 Cards per player.
Limits: Maximum of 3 copies of any single card. Duplicate cards often trigger special "Escalation" rules.

2. Card States

Ready: Card is vertical.
Unready (Exhausted): Card is horizontal.
Face Down: Always considered Unready.
History/Setback Pile: Cards removed from play due to failure or consequences.
Trials/Trophy Pile: Cards removed from play due to success (Trophys).
Discard Pile: Cards removed from play ("Out of Game") due to cycling or mechanics.

3. The Resolution Engine (2D6)

The game utilizes a bell-curve probability system similar to the Cepheus Engine, but focuses on the margin of the roll rather than binary pass/fail.

The Formula: (2D6 + Attribute + Skill + Asset Bonuses) - (Target Number) = Effect

Calculating the Outcome

Success Effect (SE): If the result is 0 or higher, the action is a Success.
- Calculation: Total Roll - TN = SE.
- Example: Rolling a 12 against a TN of 10 results in +2. This adds 2 points to the Scene's Accumulated Success Effect (ASE).
Fail Effect (FE): If the result is -1 or lower, the action is a Failure.
- Calculation: TN - Total Roll = FE.
- Example: Rolling a 7 against a TN of 10 results in -3. This adds 3 points to the character's Accumulated Failure Effect (AFE).

Criticals & Modifiers

Critical Success (Boxcars): Rolling natural double 6s. Calculate the SE normally, then double it.
Critical Failure (Snake Eyes): Rolling natural double 1s. Calculate the FE normally, then double it.
Advantage: Roll 3D6 (or two sets of 2D6), keep the best result.
Disadvantage: Roll 3D6 (or two sets of 2D6), keep the worst result.
Unskilled Penalty: Attempting a Move or Action without a relevant Asset or Skill incurs a -3 DM (Dice Modifier) to the roll before calculating the Effect.

The Consequence Mechanic (The Setback Loop)

Failures in this game are cumulative and dangerous.

Tracking AFE: Each player maintains a running total of their Fail Effects during a Scene.
The Setback Threshold: For every 5 points of AFE a character accumulates, they trigger a Setback.
- Trigger: When AFE hits 5, 10, 15, etc.
- Cost: The player must immediately take a "Ready" (face-up) Asset Card from their hand or play area and move it to their Setback Pile.
- Narrative: This represents equipment breaking, exhaustion, morale failure, or losing the tactical advantage.
- Carry Over: If you have 4 AFE and take a hit for 3 FE (Total 7), you trigger one Setback (at 5) and keep 2 AFE on the track.

III. Game Structure: Adventures & Scenes

1. Hierarchy of Play

Campaign: A linked series of games.
Adventure: A single game session.
Scene (Turn): A distinct challenge or "room" within the Adventure.
Round: The granular exchange of Moves and Actions within a Scene. Players decide who goes first, they decide which EC they try to overcome.

2. The Scene Mechanics

An Adventure consists of varying Scene Levels (typically 3 for a short game, 5 for a long game).

Base Difficulty: The default Target Number (TN) is 10.
Escalation: The TN increases by +1 for every Scene Level past 1.
Generating the Scene:
1. At the start of a Scene, each player draws Environment Cards (EC).
2. Players roll 2D6. The highest roller becomes the Primary Focus.
3. Primary EC: The card drawn by the Primary Focus player sets the main stage. Its Accumulated Success Effect (ASE) requirement is usually 10+. This card dictates the nature of Failures and Setbacks for the scene.
4. Secondary ECs: All other drawn cards become Secondary complications.
  - Each Secondary EC adds +1 to the Scene TN.
  - Secondary ECs are equal to the Floor TN of the Scene.
  - Secondary ECs usually require half the ASE of the Primary to clear.
  - Clearing a Secondary EC reduces the Scene TN by 1.

3. Success and Failure Accumulation

The game does not use binary "Pass/Fail." It uses Accumulation Tracks.

Accumulated Success Effect (ASE): The margin of success on rolls adds points to the EC's Success Track. When the Track fills, the card is overcome. The Player with the highest contribution places the cleared EC in their Trials/Trophy Pile.
Accumulated Failure Effect (AFE): The margin of failure adds points to the players' Failure Track.
- The Setback Threshold: For every 5 points of AFE, the character suffers a Setback.

4. Setbacks & History

Setbacks are not just hit points; they are narrative consequences represented by cards.

The Mechanic: When a player takes a Setback, they must take a "Ready" Asset Card (AC) from their hand or play area and place it in their Setback Pile.
The History Pile: The Setback Pile represents the "History" of the adventure—tools broken, morale lost, contacts burned.
Curses: If a player has no ACs to place in the Setback Pile, they suffer a Curse. The Domain of the current Primary EC determines the nature of the Curse (e.g., a "Martial" EC causes a "Maimed" Curse), which imposes permanent Disadvantage on related rolls.
Ghost of Failure: If an AC is in your Setback Pile, and you draw a duplicate of that AC later, you may suffer penalties (The "Once bitten, twice shy" rule). At the end of a Scene you can use an AC of the same card to move that Setback into the Discard pile (showing overcoming the Setback).

IV. The Seven Domains

Characters interact with the world through 6 Core Domains and 1 Modifier Domain (Magic). A character's build is defined by which Domains their Assets support.

1. The Core Domains

Each Domain has specific Moves (Positioning/Setup) and Actions (Execution/Resolution).

Martial: Combat, violence, physical defense. (Skills: Melee, Gun Combat, Heavy Weapons).
Evasive: Stealth, speed, dodging, escape. (Skills: Stealth, Athletics, Drive).
Social: Charm, interrogation, influence. (Skills: Persuade, Carouse, Streetwise).
Civic: Politics, law, bureaucracy, leadership. (Skills: Admin, Advocate, Diplomat).
Covert: Espionage, theft, sabotage. (Skills: Deception, Electronics, Security).
Technical: Crafting, labor, healing, repair. (Skills: Medic, mechanics, Science, Survival).

2. The Arcane (Magic)

Magic is not a standalone solution; it is a Modifier.

Low Magic Default: In the standard setting, Magic is rare and time-gated.
Example - Domain specific Blessings/Spells: Can typically only be played in Scene 3 or later.
Artifacts: Major magic items typically cannot enter play until Scene 5.
Function: Magic cards must be attached to a Core Domain action (e.g., Casting "Silence" on a "Covert Move") to grant bonuses or ignore specific EC Tags.
A number of tags fall under Magic/Arcane.
Psionics falls under Arcane/Magic Domain.

V. Card Anatomy

Environment Cards (EC)

Header: Name | Domain | Type (Place, Event, Creature).
Tags: Keywords that block specific approaches (e.g., [Shielded] blocks Martial Actions).
Triggers:
- Escalation: "If this card appears in Scene 3+, draw an additional EC."
- Domain Focus: "Martial Skills roll at Advantage against this card."
Tracks: Success (ASE) and Failure (AFE) thresholds.

Asset Cards (AC)

Header: Name | Domain | Type (Item, Skill, Trait).
Unlock Level: The Scene Level required to play this card (e.g., "Level 3" means it cannot be used in Scenes 1 or 2).
Mastery Bonus:
- Rank 1 (1 card): Standard Effect.
- Rank 2 (2 cards): Improved Effect.
- Rank 3 (3 cards): Master Effect.
Setback Interaction: "If a copy of this card is in your History/Setback pile, you cannot use its Special Ability."
Techniques: Specific bonuses (e.g., "Forest Footfalls: +2 Stealth in Wilderness ECs").

VI. Scalability & Multiplayer

The Physics of Meetings: While the system supports unlimited players, table dynamics degrade past 6-7 people.
The Lobby System: For groups of 8+, the game splits into Parallel Adventures.
- Players exist in a shared "Lobby" (Discord channel or physical room).
- Groups run separate adventures simultaneously.
- Cross-Talk: Players can spectate or exchange intel between tables during downtime.
- Global Events: A "Tournament Host" can play a Global EC that affects all parallel tables simultaneously (e.g., "An Earthquake hits the entire region").