Below is an example of a simple game implemented as a single HTML file using JavaScript. The game is called "Dead Dog Jumper" and it can be played on a smartphone. Pictograms have been used for visual representation. Please note that this is a basic implementation and can be expanded upon to make it more engaging.
In this simple game, the player controls a dog named "Dead Dog" who needs to jump over obstacles as they appear. The player can tap on the jump button to make the dog jump and increase their score. The goal is to keep the dog from touching the ground. The game provides visual feedback on the score, and when the dog touches the ground, it will display an alert with the final score.
Note: This is just a basic implementation to give you an idea. You may need to customize the visual elements, adjust timings, and add more features to make it a full-fledged game.