We could create a simplistic typology of adaptations based on what they retain of the original. Faithful adaptations, like the pious miniseries that BBC produced in the 60s and 70s, try to retain as much of the original as possible. Then, on the one hand, we have adaptations that attempt to recreate the original narrative in a different setting (Clueless, Romeo Must Die, Sparkhouse); and on the other hand, we have are things like unofficial sequels, retellings with different endings, and parodies of various sorts that diverge from the narrative structure of the original but retain a link to it through things like setting, personality of characters, and, more generally, the “world” in which it is set.
I’m not sure that this scheme will hold up to scrutiny. The problem is that the “world” of a novel often seems to carry particular expectations about how the plot might unfold. This is especially apparent in the trailer for that Jane Austen movie, in which the main character seems to believe that Jane Austen’s “world” has a distinctive narrative logic that dictates what types of stories might be told there. The heroine always gets married at the end—and even if she doesn’t, that turn of events will be judged against the expectation that she does. I am particularly interested in how this plays out in fanfiction. The attempt to write not just a novel that was inspired by Jane Austen, but a new Jane Austen novel—as many have effectively attempted to do—would seem to involve following a set of rules that have been abstracted away from Austen’s work. My question is, how do people determine what they can and cannot do in an attempt to imitate a particular author? And is this different from the way people write original novels?