Sure! Here's a simple example of a game called "Dot Sniper." It's a single HTML file with embedded JavaScript code. The game involves finding and clicking on a dot to score points. If you click on nothing, you lose a point. The dots will not disappear, but they will keep appearing randomly on the screen. You can play it on a smartphone by opening the HTML file in a web browser.
Here's the code:
Score: 0
To play the game, save the above code in a file named "dot_sniper.html" and open it in a web browser on your smartphone. The game area will appear as a 400x400px box, and dots will randomly appear within it. Clicking on a dot will increase your score by one and remove the dot. If you fail to click on any dot within one second, you will lose a point. Your current score is displayed at the top.