[gondaloof]

You don't need a prompt, you just need user interaction, which in this case is click, tap or key press.

[rpastuszak]

Yup, that's one of the reasons I added the intro modal with a call-to-action:)

The handler triggering full screen (el.requestFullscreen) needs to be in the same call stack as a user interaction event. Same with triggering audio playback programmatically.

I'm actually using audio as a fallback to prevent the device from falling asleep (via nosleep.js, modern APIs do exist, but I don't trust Apple with PWAs).