Sure, here's an example of a simple game implemented as a single HTML file using JavaScript and enclosed in script tags:
This example creates a simple game where the player is represented by a square on a canvas. The player's position is updated based on touch events on a smartphone screen. The game loop continuously redraws the canvas and updates the player's position based on user input.
Please note that this is a basic example to demonstrate the game mechanics and does not include advanced features or scoring systems. You can modify and expand on this code to create a more complete game.