Sure, I can assist you in creating a simple game where you can play as the moon protecting the Earth from asteroids. Here's an example of a single HTML file using JavaScript:
The provided code sets up a simple game scene where the moon (represented by a gray circle) can be controlled by either arrow keys or by moving the mouse. The objective is to protect the Earth (represented by a blue circle) by avoiding collisions with the red asteroids. If a collision occurs, a game over message is shown, and the game is reset.
Please note that this is a basic implementation to showcase the game mechanics. You can further expand and customize it to suit your preferences and add additional features like scoring, different levels, etc.