Good thriller, up until (spoiler)

the big reveal and the ending, which happened almost simultaneously. I kept wondering what was going on - was someone messing with her, was she crazy? The acting was spot-on, the cinematography was great, etc etc. But then, she easily finds out she was a surviving twin, that one had to be aborted, and then her dad says "oh yeah, you had a twin, I had to abort her, and she's been visiting me your whole life, you're not crazy, she's real, but don't look her in the face or she'll steal your identity." What the what? How does an aborted fetus manifest itself in real life? And how is it that the dad knows about this and it's no big deal? And how does he know about not looking her in the face? So of course it's not a surprise at the end that it's the aborted twin who's taken her life, and she's stuck in a mirror.

Another "what??" part of the movie: The mom is having an affair, in a car, in the parking lot of her flat, in plain view so her husband and daughter can see it through the window. Couldn't she go to her lover's house? Or at least park around the corner?

I don't know, I think this movie had potential, but really failed over all.