Sure, here's an example of a simple game implemented in a single HTML file using JavaScript:
This game consists of a tornado (represented by a container div) and 12 balls inside it. The aim of the game is to prevent the balls from reaching the bottom of the tornado. The tornado can be controlled by swiping horizontally on a smartphone. Once a ball reaches the bottom, a Game Over alert is shown, and the game can be reset by reloading the page.
Please note that this is a basic example and can be further customized and enhanced according to your requirements.