Sure! Here's an example of a simple game in a single HTML file using JavaScript, enclosed within script tags. The game is about a boy who wants to be a bodybuilder.
This code sets up a simple game where the player controls a boy represented by a red square on a canvas using arrow keys on a smartphone. The player can move the boy around within the canvas boundaries. The game continuously updates the player's position and redraws the canvas accordingly.
Please note that this is a basic example, and you can enhance it by adding more features, levels, and graphics as per your requirements.