Play it here, no account: https://overflow.games/unison/?door=lemmy-webgames

Open it on a laptop or a TV and every phone that scans the QR gets its own strings of one guitar. Tap a dot when it reaches its ring and the big screen plays your note; miss it and the song has a hole. In the clip four phones play House of the Rising Sun, and at 0:12 the phone holding the bass strings leaves. The song keeps going without them.

The clip is four phone screens recorded in a browser, not a filmed room. With real friends it gets messier, which I think is the fun part. One phone alone plays every string.

I'd love to hear where it falls apart with your friends.