Top-down alien shooter · gemma-4-26b-a4b-it

The user wants to build a top-down alien shooter using Phaser.
The game should be contained in a single `index.html` file.
No external assets, CDNs, or network requests.
Use `phaser.min.js` which is already in the current directory.

Requirements:
- WASD movement.
- Aim toward mouse pointer.
- Fire with left mouse button.
- Display controls on screen.
- Playable arena, player, and alien waves.
- Aliens advance toward the player.
- Player shots damage aliens.
- Contact with aliens damages player.
- Display health, score, and wave number.
- Award points for kills.
- Wave progression: harder waves.
- Game-over state with Restart.
- Procedural graphics (Phaser Graphics).
- Verify: movement, aiming, firing, alien advancement, projectile hits, UI updates.

Plan:
1.  Check if `phaser.min.js` exists.
2.  Create `index.html` with the Phaser game logic.
    -   Include `phaser.min.js` via `<script src="phaser.min.js"></script>`.
    -   Implement the game using Phaser.
    -   Procedural graphics for player, aliens, and projectiles.
    -   Game logic: movement, rotation, shooting, collision detection, wave management, UI.
3.  Test the game using `browser` tool.

Let's start by checking for `phaser.min.js`.

Okay, `phaser.min.js` is there.

Now I will write the `index.html`.

I'll structure the code:
- HTML boilerplate.
- CSS for the game container/UI.
- Script tag for `phaser.min.js`.
- Script tag for the game logic.

Game logic details:
- `Phaser.Scene` for the main game.
- `preload`: generate textures using `graphics.generateTexture`.
- `create`:
    - player (sprite)
    - cursors/keyboard input
    - groups for bullets and aliens
    - UI (health, score, wave)
    - mouse pointer for aiming
- `update`:
    - move player
    - rotate player to mouse
    - move bullets
    - move aliens towards player
    - check collisions
- `wave system`:
    - spawning aliens
    - checking if wave is cleared

Let's start writing the code.

I've written the code. It's a single-file `index.html` containing the game logic.
I noticed a small issue in my logic: `enemiesToSpawn` is not reset correctly or used in a way that makes the next wave start properly. Also, the `setSpeed` and `setHealth` additions to `Phaser.Sprite.prototype` might be problematic if not handled correctly. I should probably handle the properties directly on the sprite objects.

Let's refine the code to be more robust.
- Instead of extending `Phaser.Sprite.prototype`, I'll just assign properties directly to the object.
- I'll fix the wave logic.
- I'll ensure bullets are destroyed when they leave the screen.

Wait, I used `Phaser.Sprite.prototype` which is not ideal for a single-file script where I should be careful. Let's just use `alien.setData('speed', speed)` or just assign properties to the object.

Let's rewrite the `index.html` with a cleaner implementation.

Improvements:
1.  Use `setData` for alien properties.
2.  Fix the wave logic.
3.  Ensure the player rotation is correct.
4.  Add a "game over" button that works.
5.  Ensure procedural graphics are properly centered.
6.  Fix the bullet cleanup (using `worldbounds` or similar).

Let's review the code.
```javascript
        function startWave() {
            waveActive = true;
            enemiesToSpawn = 5 + wave * 3;
            spawnAlienWave.call(this);
        }

        function spawnAlienWave() {
            let spawned = 0;
            const interval = setInterval(() => {
                if (spawned >= enemiesToSpawn) {
                    clearInterval(interval);
                    return;
                }
                
                const x = Math.random() < 0.5? 0 : 800;
                const y = Math.random() * 600;
                const alien = aliens.create(x, y, 'alien');
                alien.setData('speed', 100 + (wave * 10));
                
                spawned++;
            }, 1500 / (1 + wave * 0.5));
        }
```

Wait, I noticed that in `update`, I am using `alien.speed`. I should use `alien.getData('speed')`.

Let's redo the file. I'll make sure it's robust.