Sure, here's an example of a simple gun game implemented in a single HTML file using JavaScript and enclosed in script tags:
This code creates a simple gun game where the player's position is controlled using the device's orientation (assumes smartphone operation). The player must move their device to aim and touch the screen to shoot. The goal is to destroy all the targets on the screen by touching them with the player's position.
Note: This example only demonstrates basic functionality and can be further enhanced with more features, design improvements, and additional game mechanics.