A comprehensive Claude skill for evaluating and enhancing FPS game designs using John Carmack and John Romero's foundational principles from id Software (1990-1996).
The Car-Mero Building Principles skill brings the legendary design philosophy of John Carmack (technical genius) and John Romero (design visionary) to your FPS game development. This skill embodies the principles that created Wolfenstein 3D, Doom, and Quake—games that defined the first-person shooter genre.
Named "Car-Mero" as a portmanteau of Carmack and Romero, this skill provides comprehensive assessment and enhancement recommendations for FPS game designs, evaluating them against 10 key dimensions organized into 4 weighted tiers.
The Car-Mero Building Principles skill:
- Evaluates FPS game designs against proven id Software principles
- Scores each dimension from 1-5 with weighted tier analysis
- Identifies critical gaps requiring immediate attention
- Recommends specific, actionable improvements with examples
- Generates comprehensive README_CR.md assessment reports
- Speed-And-Flow - Movement at 50+ mph with instant response
- Fun-First - Core 30-second loop is intrinsically enjoyable
- Weapon-Balance - Every weapon stays useful throughout the game
- 60fps-Locked - Minimum 60fps, worst-case performance matters
- Latency-First - Input-to-action under 50ms
- Simplicity-Over-Cleverness - Readable code, functions under 50 lines
- Level-Horseshoe - Non-linear layouts with natural guidance
- Contrast-Everywhere - Height, lighting, space, intensity variation
- Secrets-Integral - Multiple secrets per level rewarding exploration
- Polish-As-You-Go - Always shippable code, bugs fixed immediately
- Clone this repository:
git clone https://github.com/MushroomFleet/Carmack-Romero-BuildingPrinciples-skill.git- Copy the skill to your Claude skills directory:
cp -r Carmack-Romero-BuildingPrinciples-skill /path/to/claude/skills/user/carmero-building-principles- Download the repository as a ZIP
- Extract and upload the skill folder through Claude's skill management interface
Activate the skill with any of these trigger phrases:
- "using Car-Mero Building Principles"
- "using Carmack-Romero principles"
- "CarmeroBuildingPrinciples"
Then provide your FPS game design document, GDD, level design specification, or mechanics document.
You: "I have an FPS game design document. Can you assess it using Car-Mero Building Principles?"
Claude: [Reads the skill documentation, evaluates your design across all 10 dimensions,
and generates a comprehensive README_CR.md with scores, gap analysis, and
specific enhancement recommendations]
- Game Design Documents (GDDs) - Overall game plans
- Level Design Specifications - Map layouts and flow
- Mechanics Specifications - Combat and movement systems
- Technical Specifications - Performance and architecture
- Weapon Design Documents - Arsenal balance and progression
- Complete Game Plans - Comprehensive development proposals
The Car-Mero methodology prioritizes:
- Technical excellence serves gameplay (Carmack's engine work enabled Romero's design)
- Speed and responsiveness are non-negotiable (Doomguy at 57 mph)
- Every weapon must stay useful (no linear power progression)
- Level design guides without hand-holding (horseshoe layouts, landmarks)
- The action itself must be enjoyable (not just the outcome or progression)
From Carmack:
- Locked 60fps minimum (worst-case performance matters)
- Input latency under 50ms
- Simple, readable code over clever tricks
- Start each generation fresh (no technical debt)
- Modding as design philosophy
From Romero:
- Build the first level last
- Eight rules of level design
- Horseshoe layouts for guided non-linearity
- Contrast everywhere (height, light, space, intensity)
- Multiple secrets per level
The skill is built on comprehensive research documented in:
references/carmack-romero-research-report.md
This 600+ line research document synthesizes:
- Carmack's .plan files (1996-2010)
- GDC postmortems and presentations
- "Masters of Doom" by David Kushner
- "Doom Guy: Life in First Person" by John Romero
- id Software's 11 programming principles
- Documented quotes, design decisions, and development history
The grounding document provides the authoritative foundation for all assessment criteria and recommendations.
carmero-building-principles/
├── SKILL.md # Main skill definition
├── README.md # Skill-specific documentation
├── assets/
│ └── README_CR_template.md # Output template
└── references/
├── design-philosophy.md # Core Carmack-Romero methodology
├── technical-principles.md # Carmack's technical philosophy
├── level-design-principles.md # Romero's level design rules
├── implementation-principles.md # id Software process
├── assessment-protocol.md # Dimension scoring rubrics
├── output-template.md # README_CR.md format
└── carmack-romero-research-report.md # Full research corpus ⭐
When you submit a design for assessment, the skill generates a comprehensive README_CR.md containing:
- Executive Summary - Overall score and key findings
- Dimension Scores Table - All 10 dimensions with status (✓/⚠/✗)
- Tier Analysis - Weighted averages by tier
- Critical Gaps - Detailed analysis of dimensions scoring < 3
- Enhancement Recommendations - Prioritized, actionable improvements
- Enhanced Plan - Rewritten plan incorporating recommendations
- Implementation Roadmap - Quick wins → Medium-term → Long-term
If Tier 1 (Core Gameplay) scores below 3.0 average:
- Assessment flags FOUNDATION FAILURE
- Core gameplay must be fixed first
- All other improvements are secondary
- Movement speed, fun-first loop, and weapon balance are paramount
This mirrors id Software's ruthless cutting of features that didn't serve the "soul" of the game (e.g., stealth mechanics cut from Wolfenstein 3D despite being functional).
What makes id Software FPS games distinctive:
- Instant response to input
- Movement faster than contemporary games (50+ mph)
- No action flow interruptions
- Instant weapon switching (no animations)
- Health/ammo pickups (no regeneration)
- Fast doors that open on approach
- Clear visual feedback for damage
- Aggressive AI that closes distance
The skill is grounded in primary and secondary sources:
Primary Sources:
- John Carmack's .plan files (archived)
- GDC Vault presentations (Doom, Quake, Wolfenstein postmortems)
- John Romero's GDC 2016 talk "The Early Days of id Software"
- QuakeCon keynotes
Secondary Sources:
- "Masters of Doom" by David Kushner (2003)
- "Doom Guy: Life in First Person" by John Romero (2023)
- "Game Engine Black Book" series by Fabien Sanglard
- Technical documentation and archived interviews
Contributions are welcome! If you have additional research, documented quotes, or refinements to the assessment criteria, please submit a pull request.
Areas particularly welcome:
- Additional documented Carmack/Romero quotes with sources
- GDC talk transcripts and analysis
- Refinements to scoring rubrics based on historical examples
- Case studies of games that embody (or violate) these principles
This project is licensed under the MIT License - see the LICENSE file for details.
- John Carmack - For the technical foundation and relentless optimization
- John Romero - For the design philosophy and "if it's not fun" mantra
- id Software - For revolutionizing FPS design (1990-1996)
- David Kushner - For documenting the history in "Masters of Doom"
- The Doom Community - For 30+ years of keeping the philosophy alive
Other building principles skills in this series:
- Torvalds Building Principles (systems programming)
- Braben Building Principles (procedural generation)
- FromSoftware Building Principles (difficulty and fairness)
- Kojima Building Principles (narrative-mechanical fusion)
- Toriyama Building Principles (character and visual design)
"The action itself must be fun. If the core loop isn't enjoyable in 30 seconds, the 30-hour campaign won't save it."
If you use this codebase in your research or project, please cite:
@software{carmero_building_principles,
title = {Car-Mero Building Principles: FPS Game Design Assessment Framework},
author = {Drift Johnson},
year = {2025},
url = {https://github.com/MushroomFleet/Carmack-Romero-BuildingPrinciples-skill},
version = {1.0.0}
}