Well, the whole thing with Margaret was just @@. I'm not really sure I buy into the whole wondertwin super power or maybe I don't want to because my own twins have shown none of that kinship. Is it because they are boy & girl and not girl girl? Or is the whole concept hokey? I think a real twist would have been to have Margaret obsessed with twins, only to find out that she was wrong or that what she thought was true was not. That there was no special twinness missing from her life, no twin after all. That her void has to do with her own longing for specialness.
I think both Adeline and Emmeline were so enmeshed not because they were twins, but because of the criminal neglect of them. They relied on each other because they only had each other. And I guess I think the implication that their not-rightness had to do with the incestuous relationship of the parents also sort of meh or at the very least an easy out. Again, I guess I'm more of a nurture person than a nature person.
Maybe I don't read "twin" stories well because of my own?