Sure, here's a simple game implemented as a single HTML file using JavaScript. The game involves tapping a green block in the middle of the screen, and it generates random blocks across the screen. The blocks will disappear when tapped.
To run the game, you can save the code into a file with a `.html` extension, and then open the file with a web browser on your smartphone. When you tap the green block in the middle of the screen, random red blocks will appear across the screen. Each generated block can be tapped to make it disappear.