Sure, here's a simple game implemented as a single HTML file with JavaScript:
When you open this file in a browser, it will display a canvas with a ball bouncing around inside. The ball will start at the center and initially move at a speed of 5 pixels per frame. Every time the ball hits the edge of the canvas (left, right, top, or bottom), it will bounce back and increase its size and speed. The game will continue indefinitely until the browser tab is closed.
Feel free to customize the appearance, add more features, or improve the game logic based on your requirements.