Sure! Here's an example of a simple shooting game implemented as a single HTML file using JavaScript:
In this game, you control a player at the bottom of the screen and shoot bullets towards an enemy at the top. The goal is to hit the enemy with the bullets.
To play, you can drag the player left or right using touch gestures on your smartphone. To shoot a bullet, simply release your finger from the screen. When you hit the enemy, you win and the game restarts.