Build a complete Phaser 3 platformer in a single index.html. Check whether phaser.min.js exists in the directory, and check the version if needed.

Building a full platformer. A single index.html file with procedural graphics (generated with Graphics), player physics, a camera that scrolls in a side-scrolling manner, enemies, coins, and a goal flag.

Design:
- Canvas 960x540, world around 6000 wide.
- Tile-based levels defined with strings.
- Graphics-based textures: brick, ground, pipe, coin, player (simple character), enemy (Goomba-style), flag.
- Player: run with arrow keys / A-D, jump with space / up. Coyote time? Keep it simple.
- Enemies patrol on platforms, can be defeated by stomping. Hitting from the side takes damage / knockback, lives system.
- Coin collection, score.
- Flagpole at the goal → win screen.
- HUD: score, coins, lives.

Writing carefully with Phaser 3 API. Checking the Phaser version — minified, 1.18MB → probably Phaser 3.60+. No problem.

Writing the file.

I ended up writing a messy draft that contains placeholder hacks (randomized tex keys, undefined groups, references to this.tx before it's created, etc.). I should properly rewrite the entire file from scratch: give the textures explicit, stable keys, and create the groups before iterating over them. Let's do a full clean rewrite.