As an AI language model, I can provide you with an example of a simple game implemented as a single HTML file with JavaScript. Please note that this is just a basic example and not a complete game. Here's the code:
This code sets up a simple game where you control a square player using arrow keys on a smartphone. The player moves within a canvas element. The game loop continually updates the canvas and handles input to move the player's position accordingly.
Please note that this is a very basic implementation, and you can expand on it to create a more complex and enjoyable game.