Zero Day Rules

Goal: Reach any edge node on the board boundary.

Midpoint: Exploit

When Attack token reaches firewall:

1. Replace Attack token with Exploit token (automatic, no action cost)
2. Exploit token remains at this location permanently
3. Continue with remaining actions if any

Phase 2: Ghost

Move Ghost token away from the Exploit position.

First move after Exploit:

1. Place Ghost token at Exploit location
2. Move Ghost away in the same Move action

Goal: Maximize distance (path segments) between Exploit and Ghost.

Board Layout

Digital Implementation (Board SDK)

Target display: 1920×1080 pixels (landscape, 16:9)

Horizontal Layout

┌────────┬──────────┬────────────────────────────┬──────────┬────────┐
│Blue UI │ Blue Res │       5×5 PLAYABLE GRID    │ Red Res  │ Red UI │
│        │ (5 tiles)│    Purple "Firewall"       │ (5 tiles)│        │
│        │          │    Center tile pre-placed  │          │        │
└────────┴──────────┴────────────────────────────┴──────────┴────────┘
← Blue player sits here                      Red player sits here →

• Reserve Pools: Left (Blue) and Right (Red) for drawn tiles - visible to both players
• Playable Grid: 5×5 center area for tile placement
• Firewall: Purple border - reaching it completes Phase 1
• Starting Tile: Center position [2,2] with game-tile-13-center

Player Orientation

• Blue player: Views from LEFT side
• Red player: Views from RIGHT side

Tile System

Properties

• Quantity: 25 total (1 starting + 24 placeable)
• Size: 200×200 units (2.0 world units at 100 PPU)
• Edge Nodes: 4 per tile (Top, Right, Bottom, Left midpoints)

Path Segments

By Shape:

• Quarter-curve: Connects adjacent nodes (90° apart) - e.g., Left→Top
• Straight line: Connects opposite nodes (180° apart) - e.g., Left→Right

By Color:

Path Matching Rules

At connecting edges:

• Red ↔ Red: Valid
• Blue ↔ Blue: Valid
• Purple ↔ Any: Valid
• Red ↔ Blue (exclusively): Invalid

Once placed, tiles cannot be moved, removed, or rotated.

Token System

Three Tokens Per Player

Token Rules

• Always reside on edge nodes (never inside tiles)
• Edge node must include path of player's color OR purple
• Both players' tokens may occupy same node
• Tokens do not block each other

Action System

Turn Structure

Each turn: Two Single Actions OR One Double Action

Single Actions

Double Action: Place

• Place tile on any empty space adjacent to token's tile
• Can connect to any side (not just token's edge)
• Consumes entire turn

Movement Rules

1. Color Restriction: Only traverse own color OR purple
2. Single Color Per Move: Stay on one color within a Move action
3. Color Junction: At nodes where both colors continue:
   • Continue on current color, OR
   • End Move action, then use another Move to switch
4. Path Length: Unlimited distance along continuous same-color path
5. Non-blocking: Opponent tokens don't block

Game End and Scoring

End Trigger (in sequence)

1. Deck is empty
2. One player ends turn with no tiles in reserve
3. Other player takes final turn

Scoring

1. Find path between Exploit and Ghost tokens
2. Count segments of player's OWN color (not purple)
3. Each quarter-curve or straight line = 1 segment
4. Most segments wins

Tiebreaker

If tied, player with most purple segments wins.

Setup Sequence

1. Determine first player and colors
2. Seat by color (Blue on left side, Red on right side)
3. Place Attack tokens on starting tile's matching color nodes
4. Each player draws 5 tiles
5. First player: Place 1 tile adjacent to center, keep 3 in reserve, shuffle 1 back
6. Second player: Same as first
7. Both flip reserve tiles face-up

Digital Implementation Notes

Validation Requirements

• Tile Placement: Validate color matching at all connecting edges
• Movement: Enforce single-color continuity per Move action
• Token Position: Ensure edge node has valid path color

Phase Transitions

• Attack→Exploit: Automatic when Attack reaches firewall edge
• Exploit→Ghost: First Move action after Exploit placement

Additional Resources

Reference Files

This skill's references/ folder contains:

Important: The official rulebook describes the original physical game with a portrait orientation (Blue at top, Red at bottom). The digital Board SDK implementation uses landscape orientation (Blue on left, Red on right) to fit the 1920×1080 display. Game mechanics are identical; only the physical layout differs.

Key Algorithms

• Placement validation (color matching at edges)
• Movement validation (path continuity)
• Score calculation (path finding between tokens)

Request consultation from the code-architecht subagent or the project-architecture skill for C# code examples of these algorithms.