I was thinking that for realism there could be spectators, only in tournaments and not practice, ranked or challenge games. They could just be static overlays superimposed on the photos and have no actual effect on gameplay. Sound effects would be cool though. For maximum realism, there should be occasional quieter cheers and "awwww"s unrelated to action on the screen (as at real tournaments, when such things are often heard in response to action taking place on a nearby hole).