Sure! Here's a simple game implemented as a single HTML file using JavaScript, enclosed in script tags. The game is called "Mask Gun" and it can be played on a smartphone. The game involves shooting masks at virus pictograms to eliminate them.
To play the game, simply open the HTML file on a smartphone using a compatible web browser. The player can control the blue rectangle (representing the player character) using the right and left arrow keys. The goal is to stop the red virus pictograms from reaching the player by shooting green rectangle masks at them. Colliding with a virus will end the game, while successfully hitting a virus with a mask eliminates it and spawns a new one.