Thanks for the feedback!
Yeah, it seems like Safari on iOS doesn't fully supports fullscreen :( That's unfortunate.
As for the sound, again it seems like another limitation of Safari on iOS that requires a user gesture (tap or click) in order to play each sound. See https://stackoverflow.com/questions/53059288/safari-browser-audio-play-is-not-working. I'll try to code a workaround. I don't have an iPhone so I might need you test again when I do.
In the meantime, see if this browser setting works: https://audiomovers.com/help/faq/i-cant-hear-any-audio-playback-in-the-safari-web-browser
Thanks for testing on your tablet. I'm currently working on adding logic that will display the fullscreen icon for tablets so you can go fullscreen if you launch the game as a desktop site.
Thanks for the suggestions :) I'll keep them in mind while working on the next test build.