I finished a second reading -- after almost 50 years! -- of Peake's Gormenghast and then read Heinlein's Farmer in the Sky. Other than maybe Red Planet, I skipped all the Heinlein juveniles when I was one myself, but have read two or three of them in the past few years and enjoyed them.
Then I read Hamlet again. I've thought of King Lear as a thought experiment (What was it like to be British before Christianity arrived?), and now I'm thinking about this play also as a thought experiment: Supposing a ghost did appear and demand vengeance to be taken, what then?
But I think we can do a thought experiment of our own with this play. Suppose the play was not called Hamlet but was called The Tragedy of Claudius King of Denmark.
So you have the story of a man who has violated hospitality, committed regicide, committed what could be counted incest -- already before the play begins. Then he commits various forms of treachery to keep the throne he usurped (e.g. sending Hamlet to England, with sealed orders that Hamlet is to be killed on the spot upon arrival).
Claudius's wickedness is so great as to evoke national calamity. The apparition of the ghost shows how dreadful is the situation for Denmark, just as apparitions do in Julius Caesar: as Claudius has profoundly violated right order, so now even the right boundary between the living and the dead is weakened and broached. As sinners generally do, Claudius thought he could manage the consequences of his wrong actions, in his case through hypocrisy, lying, and the exercise of earthly power, but he has set loose consequences he never dreamed of; he's set loose hell (or purgatory, anyway) itself. Within a short time after his murder of his brother and his marriage to the widow, Claudius finds life to be a matter of constant anxiety right up till his death.
In Claudius, Hamlet is the play's antagonist. He has been a well-liked and well-behaved young man, a good student with a romantic interest in a young woman who, unfortunately, is not a good match for him socially. If this play were about Hamlet, we would expect a lot more development of this problem, but the play is primarily about Claudius and the disaster he has unleashed upon his kingdom. Eventually it leads where it must, not only in his death and that of his paramour and his antagonist nephew, but in the kingdom's loss, as it is to become subordinated to Norway (in the person of Fortinbras).