Sure, here's a simple game implemented as a single HTML file using JavaScript. It is designed to be played on a smartphone and uses pictograms for a better visual experience. The game is called "Picto Tap" where you have to tap on pictograms as they appear on the screen to earn points. The game ends after a certain time limit.
To play the game, simply save the above code into a file with a `.html` extension (e.g., `game.html`), then open it in a web browser on your smartphone. The game will start automatically, and you need to tap on the pictograms that appear on the screen to earn points. The score and remaining time are displayed on the screen. The game will end after 30 seconds, and your final score will be displayed. Enjoy playing "Picto Tap"!