Sure! Here's an example of a simple game implemented as a single HTML file, using JavaScript and enclosed in script tags. The game involves controlling a person walking on a smartphone, and the fps (frames per second) gradually decreases, creating a challenge for the player. Pictograms are used to represent the game elements.
To play the game, open this code in a web browser (preferably on a smartphone), and you will see a person walking horizontally on the canvas. The frame rate of the animation gradually decreases every 60 frames, making it more challenging to control the character.
Note: This is a very basic example just to showcase the concept. You can expand on this by adding more game mechanics, levels, scoring, or using pictograms to represent other game elements as per your requirements.