Sure! Here's an example of a simple game implemented as a single HTML file using JavaScript. The game is designed for smartphone operation and uses pictograms as graphics. The player can tap the screen to walk and double tap to jump, while encountering enemies in a red world.
In the above code, I assume the existence of a walk_pictogram.png file for the player graphic. You can replace it with any suitable pictogram image. The player starts at the center of the screen (50% x, 50% y) and can be moved horizontally by tapping the screen. Double tapping triggers the jump function, which makes the player move upwards briefly before returning to the ground.
Please note that this is a basic example, and you can expand it further by adding enemies and more gameplay elements according to your requirements.