Sure, here's an example of a simple physics simulator game implemented in a single HTML file using JavaScript:
This game is a simple physics simulator where the player controls a square-shaped character and can make it jump by pressing the spacebar. The character falls back down due to gravity. The game is displayed on a canvas element, and the player's movement and physics calculations are handled by JavaScript.
Please note that this is just a basic example to give you an idea of how a physics simulator game can be implemented. Feel free to modify and enhance it according to your requirements.