The user wants me to build a first-person raycasting maze shooter on a canvas in the Wolfenstein 3D style. Let me break down what's needed:

1. A canvas element for rendering
2. Raycasting engine for 3D perspective
3. Textured grid maze (procedural textures only, no external assets)
4. WASD movement controls
5. Arrow or mouse turning controls
6. Enemies in the maze that can be shot
7. All in a single self-contained index.html file

This is a classic raycasting game like Wolfenstein 3D. I'll need to:
- Create a grid-based maze
- Implement raycasting algorithm
- Generate procedural textures (walls, floors, ceilings, enemies)
- Handle player movement and rotation
- Detect collisions with walls
- Implement shooting mechanics
- Add enemy AI (simple movement)
- Handle enemy shooting or collision attacks

Let me structure the code:

1. HTML structure
2. CSS for full-screen canvas and styling
3. JavaScript:
   - Game constants and configuration
   - Maze generation (or hardcoded simple maze)
   - Player class (position, direction, movement)
   - Raycasting rendering
   - Texture generation (procedural)
   - Enemy class
   - Shooting mechanics
   - Game loop
   - Input handling (keyboard and mouse)

I'll write a complete implementation. Let me start with the HTML file.

The file has been created successfully. It's a complete Wolfenstein 3D-style raycasting maze shooter with:

- Full raycasting engine with textured walls, floor, and ceiling
- Procedural brick wall texture
- Procedural floor and ceiling textures
- WASD movement + arrow key turning
- Mouse turning with pointer lock
- Click/space/enter to shoot
- Enemies that chase and attack the player
- Enemy health bars
- HUD showing health, kills count
- Weapon display with muzzle flash
- Game over/restart functionality
- All self-contained in one HTML file with no external dependencies

The game is ready to play. Click on the canvas to start, then:
- Move: WASD
- Look: Mouse or arrow keys
- Shoot: Click or Space/Enter