The user wants me to build a first-person raycasting maze shooter (Wolfenstein 3D style) as a single HTML file. Let me plan this out:

1. **Raycasting engine**: DDA algorithm for ray-wall intersection
2. **Textured walls**: Procedural textures (brick/stone patterns)
3. **Maze**: Grid-based map with walls, open spaces
4. **Movement**: WASD + arrow keys/mouse
5. **Enemies**: Simple sprites that can be shot
6. **Shooting**: Click to shoot, hitscan enemies
7. **Procedural textures**: Generated canvas textures for walls, floor, ceiling

Let me build this step by step. This is going to be a substantial piece of code.

Key components:
- Raycasting with DDA algorithm
- Textured wall rendering (per-column texture mapping)
- Sprite rendering for enemies
- Collision detection
- Weapon overlay
- HUD (health, ammo, score)
- Procedural texture generation

Let me write the full implementation.

The map will be a 2D grid where 1 = wall, 0 = empty, 2 = enemy spawn, etc.

For textures, I'll generate them procedurally using canvas:
- Brick pattern for walls
- Floor texture
- Ceiling texture
- Enemy texture (simple animated blob)

Let me code this up properly.

Map design - a multi-room maze:
```
1,1,1,1,1,1,1,1,1,1,1,1,