Sure! Here's a simple example of a game implemented as a single HTML file using JavaScript. It includes a ten-minute timer where you win and confetti appears on the screen after the timer ends:
10:00
To play the game, simply open the HTML file on your smartphone browser. The timer starts at 10:00 and counts down until it reaches 00:00. Once the timer ends, confetti will appear on the screen for 20 seconds.
Note: For the confetti effect, I've used a simple canvas-based implementation. The confetti particles are generated randomly and animated falling from the top of the screen.