Whacker

A text adventure game engine built first, with plans to generate content later. The game is free and open source software (FOSS).

When I was a kid, I wrote a game called Whacker where it was a Rogue vs. a Freeport Guard. It was text only and the user would start the fight and the two would go at it, whacking each other until one won. This is a modern engine inspired by that idea.

Quick Start

Requires Node.js.

# Install dependencies
npm install

# Run the demo (a sample combat between a Fighter and a Goblin)
npm run demo

The demo runs a turn-by-turn combat with a 6-second pause between rounds so you can watch the action unfold.

Ruleset

D&D 2024 under the System Reference Document (SRD 5.2) / CC-BY-4.0

Why SRD 5.2?

• CC-BY-4.0 is simpler — one attribution paragraph, no "Open Game Content" / "Product Identity" distinction, no full license text reproduction required
• CC-BY-4.0 is not viral — downstream users can license their own work however they want
• CC-BY-4.0 is irrevocable by design — survived the 2023 OGL deauthorization attempt through its own structure
• SRD 5.2 has more content — weapon mastery, expanded rules glossary, exploration mechanics, additional species (Goliath), additional backgrounds (Criminal, Sage, Soldier)
• SRD 5.2 aligns with 2024/5.5e rules — the current direction of D&D

What SRD 5.2 Includes

• 12 core classes with subclasses
• 7 species (Dwarf, Elf, Halfling, Human, Goliath, and more)
• 6 backgrounds (including Criminal, Sage, Soldier)
• All core spells through 5th level
• Monster manual subset (100+ monsters)
• Full combat rules, ability checks, saving throws
• Weapon mastery mechanics
• Exploration mechanics
• Rules glossary
• Equipment, magic items, conditions

Future AI-Generated Content

• Additional classes/races beyond the SRD
• Campaign-specific content
• Custom monsters and NPCs
• Adventure modules

Architecture (Planned)

├── main.ts              # Game loop
├── llm.ts               # OpenRouter client wrapper (future)
├── game_state.ts        # World state, inventory, history
├── prompts.ts           # System prompt templates (future)
├── summarizer.ts        # Context compression (future)

Architecture

The project is split into two layers:

• Engine — a content-agnostic game engine (MIT licensed). Handles combat resolution, character state, dice, and event emission.
• Game content — data and content that plugs into the engine. Lives in clearly marked directories.

This separation means the engine can be extracted into its own package/repo independently of any game content.

Licensing

Layer	License	File
Code (engine + game code)	MIT	LICENSE
SRD 5.2 game content	CC-BY-4.0	LICENSE (attribution section)
Original game content	CC-BY-4.0	LICENSE (declared)

Game mechanics (ability scores, AC, HP, attack rolls) are not copyrightable. SRD 5.2 content is used under CC-BY-4.0. Original content created for this project is released under CC-BY-4.0.

Development Principles

1. Build the engine first — no AI dependency for core gameplay
2. Use SRD 5.2 as the mechanical foundation
3. Design for AI content injection later (monsters, NPCs, quests, items)
4. Keep it FOSS and community-friendly
5. Maintain clean separation between engine code and game content