Build a game like Geometry Dash with Claude Code

Build an original browser game in the same genre as Geometry Dash: a rhythm-based platformer. Use your own name, characters, art, sound and levels. Only the general mechanics should feel familiar; do not copy Geometry Dash's name, characters, art, music or level layouts.

Version one should have:
- Auto-running square
- Jump to the beat
- Spikes and pads
- Levels synced to music
- Level editor

The hard part: Syncing levels to music. Use beat timestamps.

How to build it:
1. Read this folder first. If it is empty, set up a browser game with Vite, TypeScript and Phaser (or Three.js if it is 3D). Write a short PLAN.md with the game loop, entities, controls and what you are leaving out of version one.
2. Get the core loop playable before anything else: auto-running square. Use simple shapes or free placeholder art until it feels good.
3. Add the rest of the mechanics one at a time, keep game rules in pure functions you can unit test, and make it work with both keyboard and touch.
4. Add a start screen, game over, score and a saved best score in localStorage, plus sound effects you generate or that are free to use.
5. Run it, play it, tune the difficulty, fix what breaks, and finish with a summary and how to deploy it as a static site.

Paste it into Claude Code in an empty folder. It plans first, so read PLAN.md and steer before it starts building.