Sure! Here's an example of a single HTML file that contains JavaScript code to create a simple game where a bird goes up when you click the screen, and the game ends if the bird hits a pipe. There is also a countdown timer that updates every second when you pass a pipe.
You can save this code as an HTML file, run it in a web browser, and interact with the game by clicking on the screen to make the bird go up. The game will end if the bird hits a pipe, and there is a countdown timer that updates every second when you pass a pipe.