Sure! Here's an example of a simple game implemented as a single HTML file using JavaScript. The game is about a kid who gets possessed, and his two friends have to save him. In the game, you'll play as one of the friends.
To play the game, you can open the HTML file in a web browser on your smartphone. Use the arrow keys to move the friend character (green). The objective is to reach the possessed kid character (red) to save him. Once you rescue the kid, an alert message will appear, and the game will reset.
Please note that this is a simple example, and you can enhance the game by adding more features, levels, or graphics as per your requirements.