From Gwern's "solution":

Ophelia goes mad and forgets being in love with Hamlet

Dafuq?

One of the most striking aspects of the Dracula interpretation of SD is that SD turns out to be alluding to it indirectly, by making parallel allusions—the opening chapters of Dracula allude to the same parts of Hamlet that SD does! This clinches the case for SD-as-Dracula, as this is too extraordinary a coincidence to be accidental.

Yes, two different stories both alluding to the most quoted work in English goddamn literature can't be a coincidence. It's not like the line "there are more things in Heaven and Earth..." has been repeated so often that even Wolfe's narrator calls it "hackneyed"... Hold on, I'm getting a message, just let me press my finger to my imaginary earpiece....

I would say myself that Wolfe's alluding to a line rather than quoting it exactly serves to call up the whole feel of Hamlet, rather than a single moment. It evokes the Gothic wrongness, the inner turmoil paired with outer tumolt, the appearances that sometimes belie reality and sometimes lead it. You could take this as suggesting that Susie D. is the Devil in a pleasing shape. Or, with all the Proustian business, and the lengthy excursus about historical artifacts hanging on as though the past lies thick in the present and refuses to lift... Perhaps the secondary Hamlet allusion behind the obvious one is "the time is out of joint". Maybe Suzanne is a notional being, an idea tenuously made manifest, a collective imaginary friend or dream-creature leaking out into our reality. She looks the same from one generation to the next, because the dream of the girl next door stays the same. Perhaps the horror is that our reality is fragile, that these creations are always slipping in, and we only have a stable daylight world because we refuse to see them.

Also, the illustration sucks.