Sure, here's an example of a simple soccer game implemented as a single HTML file using JavaScript:
In this example, the game is played on a canvas element (`gameCanvas`). The player controls a blue rectangle at the bottom, moving it left or right using the left and right arrow keys. The objective is to bounce the black ball off the player's rectangle and prevent it from reaching the top or the sides of the canvas.
The ball constantly moves and changes direction when it collides with the boundaries of the canvas or the player's rectangle. Each time the ball collides with the player's rectangle, the player's height is decreased to make the game more challenging.
Please note that this example is fairly basic and can be expanded upon to add more features, improve gameplay, and enhance the overall experience.