Sure, here's an example of a simple shooting game implemented as a single HTML file using JavaScript. This game can be played on a smartphone and utilizes pictograms for visual elements:
To play the game, open the provided HTML file on a smartphone browser. The player can move the blue square (player) horizontally by touching and dragging on the screen. Releasing the touch will shoot a red square (bullet) from the player's position. The green squares (aliens) will move down on the canvas, and if a bullet collides with an alien, both the bullet and alien will disappear. If an alien reaches the bottom of the canvas, the game will reset, and a "Game over!" alert will appear. The game will keep running until the game over condition is met.
Please note that this is a basic example and can be further expanded and customized to enhance the game experience.