Version of Hamlet in which each character is aware of the ghost. Each has seen him at some point, or felt his presence. Any mention of the King of Denmark should make clear how thoroughly he has haunted the play. Any character who does not explicitly reference the King should indicate, by gesture, by intonation, that they are nonetheless haunted.
Version of Hamlet in which there are too many ghosts. The actors playing the other characters must constantly push through crowds of actors playing the ghosts, the latter far outnumbering the former. Each of the actors playing the ghosts repeat the ghost’s lines, constantly, without respect for when or how the other ghosts speak them. It is a booming cacophony, drowning out all other words.
Version of Hamlet in which it is unclear whose ghost the ghost is.
The ghost promises salvation, which is to say: the possibility of guilt.
Version of Hamlet in which the boundary between ghost and other is not clear. We have seen the ghost; it is a body, played by an actor; we come to suspect that the others, no more or less bodily than the ghost, when it appeared, might be ghosts as well. Finally we suspect that we are watching an empty stage.
We are watching an empty stage.