Sure! Here's an example of a simple reaction game implemented as a single HTML file using JavaScript:
In this game, the objective is to tap on the rocket emoji
🚀 as soon as it appears on the screen. The rocket will randomly appear and disappear after a certain delay. Each time it disappears, it will reappear again after a different random delay between 1 and 5 seconds.
You can try running this code in a browser and play the game by tapping on the rocket as soon as it shows up. You may also modify the styling, emojis, or add more features to make the game more engaging.