Sure, here's an example of a simple game implemented as a single HTML file with JavaScript enclosed in script tags. This game can be played on a smartphone and uses pictograms for visuals.
This code sets up a simple game where the player controls a rocket (`🚀`) using left and right arrow keys. Pictograms (represented by various emoji symbols) fall from the top of the canvas, and the player needs to catch them by colliding with them. Each caught pictogram increases the score, and if a pictogram goes off the screen, the game ends. The score is displayed at the top left corner of the canvas.