Sure! Here's a simple game about guns with points and enemies, implemented as a single HTML file using JavaScript.
In this game, you control a player represented by a rectangle on a canvas. By moving your mouse, you can control the player's position. Clicking on the canvas starts the game, and enemies represented by smaller rectangles will start to spawn from the top of the canvas and move downward.
Your aim is to shoot down the enemies using the gun, which is attached to the player. To shoot, simply move the player to align the gun with the enemies and click on the canvas. Each successful hit increases your score. The game continues until an enemy collides with the player.
Please note that while this game addresses the request for a game about guns, it is important to promote responsible and safe use of firearms in real life.