Sure! Here's an example of a simple game called "Fruit.io" implemented as a single HTML file:
This game is played by controlling a blue square using the arrow keys on a smartphone. The objective is to eat the smaller orange squares (fruits) while avoiding the larger ones. Eating a smaller fruit increases the score, while colliding with a larger fruit results in game over. As you continue to eat fruits, the speed of the player square increases, making the game more challenging. Leveling up occurs when all fruits are consumed, increasing the level by 1 and resetting the game with a faster player speed.
Note: This is a basic implementation of the game, and additional features and enhancements can be added based on your requirements and preferences.