Here is an example of a simple game implementation using JavaScript enclosed in script tags within a single HTML file:
This is a very basic template for a game where you control a red circle (the player) on a canvas using the arrow keys on your keyboard. The game loop continuously updates the game state, and the main loop uses `requestAnimationFrame` to update the game at a smooth frame rate.
Feel free to expand upon this template and add additional features to create a fully playable game.