Sure! Here's a simple game that meets your requirements:
Afk Game
Wait for 30 seconds to win the game!
To use this game, save it as a `.html` file and open it in a web browser (preferably on a smartphone for better experience). The game will start automatically and you have to wait for 30 seconds. Once you reach the 30-second mark, an alarm sound will play, and confetti will be displayed all over the screen for 5 seconds.
Note: You need to replace `"sound.mp3"` with the path to your own audio file to hear the alarm.