Sure! Here's an example of a simple game implemented as a single HTML file using JavaScript:
This game sets up a canvas element and allows the player to control a blue square using touch input on a smartphone. The player's square will follow their finger movements on the screen. The game logic and rendering are handled in the `gameLoop` function, which is called repeatedly to update and render the game.
Please note that this is a very simple example and can be expanded upon to create a more complex game with additional features and mechanics.