Implement Browser-Based Retro Shooting Game

Create a browser-based retro shooting game that runs within the web application. The game should feature classic arcade-style mechanics, pixel graphics, and engaging sound effects.

**Requirements:**
- Implement basic player controls (move, shoot).
- Include enemies with simple AI and movement patterns.
- Track score and display game over screen.
- Use retro-style graphics and sounds.
- Ensure the game runs smoothly in modern browsers.

**Technical Suggestions:**
- Use HTML5 Canvas and JavaScript for rendering and gameplay logic.
- Modularize code for easy maintenance and future enhancements.
- Optionally, integrate with existing UI if appropriate.

**Testing:**
- Test on major browsers (Chrome, Firefox, Edge, Safari).
- Confirm responsive design and smooth gameplay.
- Verify sound and graphics work across platforms.