Sure! Here's an example of a simple shooting game implemented as a single HTML file using JavaScript:
This game is designed to be played on a smartphone. You can control the player by dragging your finger across the screen. The player character is represented by a blue square, bullets are represented by red squares, and enemies are represented by green squares. The goal is to shoot down the enemies and avoid them reaching the bottom of the screen.
Disclaimer: This is a basic example of a shooting game and may require further enhancements and optimizations to suit your specific needs.