Sure, here's an example of a simple soccer game implemented as a single HTML file:
This game creates a soccer ball represented by a colored circle in the center of the canvas. The ball can be controlled by touching the screen on a smartphone. The ball moves in the direction of the touch and bounces off the edges of the canvas. The game uses JavaScript to handle user input and animate the ball's movement.
Please note that this is just a basic implementation to illustrate the concept. You can modify and enhance the game further based on your specific requirements and preferences.