add new skill game-engine

[jhauga]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, agent, or skill file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, or skill with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.

---

Description

New skill for working with and/or designing a game engine.

Testing

Full results at support-repo.

• Agent: Claude Agent
• Model: Claude Sonnet 4.6
• Number of Prompts: 1
• Post Edits: none

Prompt

Use #file:SKILL.md to create a 2d beat-em-up similar to the classic arcade game
"Double Dragon" with:

- 1 level
- 3 types of enemies spawned
- 2 intermediate bosses spawining mid-level at the same time
- 1 main boss at the end of the level

Use `svg` graphics to create the assets. Use cliche or common or typical graphics in
regards to:

- Player design, actions and attacks, and movements
- Enemy design, actions and attacks, and movements
- Level design and environmental effects

Map controls as:

- Left arrow = move left
- Right arrow = move right
- Up arrow = move up
- Down arrow = move down
- Space bar = pause
- A = jump
- S = punch

Write the new game to #file:index.html, filling the blank file with the HTML,
CSS, and JavaScript for the game. Choose best JavaScript library available to
run the game using GitHub pages.

Results

After first prompt, a working game.

---

Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• Update to existing instruction, prompt, agent, plugin, or skill.
• Other (please specify):

---

By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[Copilot]

Pull request overview

Adds a new game-engine skill to the skills catalog, providing bundled templates and reference material for building web-based games/game engines (Canvas/WebGL/JS, 2D/3D, controls, physics, publishing).

Changes:

• Introduces skills/game-engine/ with a SKILL definition plus bundled assets/ templates and references/ documentation.
• Adds multiple long-form reference docs (algorithms, techniques, web APIs, terminology, 3D, publishing, controls, engine design).
• Registers the new skill in docs/README.skills.md.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
skills/game-engine/SKILL.md	Defines when/how to use the skill and indexes bundled assets/references.
skills/game-engine/assets/paddle-game-template.md	Breakout-style Canvas template walkthrough.
skills/game-engine/assets/2d-maze-game.md	Tilt/keyboard maze game template (Phaser).
skills/game-engine/assets/2d-platform-game.md	Platformer template walkthrough (Phaser).
skills/game-engine/assets/simple-2d-engine.md	Grid-based platformer engine architecture template.
skills/game-engine/assets/gameBase-template-reop.md	Reference/overview of deepnight’s GameBase template repo.
skills/game-engine/references/basics.md	Intro/anatomy of web game development and game loops.
skills/game-engine/references/web-apis.md	Survey of relevant browser APIs for games.
skills/game-engine/references/techniques.md	Technique reference (startup perf, audio, tilemaps, collision, etc.).
skills/game-engine/references/algorithms.md	Algorithms/math reference (Bresenham, collision, vectors, physics).
skills/game-engine/references/3d-web-games.md	3D web game reference (frameworks, shaders, WebXR, collision).
skills/game-engine/references/game-control-mechanisms.md	Input/control mechanisms across devices.
skills/game-engine/references/game-engine-core-principals.md	Engine architecture/design principles reference.
skills/game-engine/references/game-publishing.md	Distribution/promotion/monetization reference.
skills/game-engine/references/terminology.md	Game dev glossary reference.
docs/README.skills.md	Adds the new game-engine entry to the skills index.

[aaronpowell]

Can you repoint this branch to be staged as the contributing docs. Here's how to do that with the GitHub CLI:

gh pr edit 792 --base staged