Voices do not change
Ok so the faces change every time she loses sight of them for an instant; I get that. But the voices do not change! She would have been able to close her eyes and LISTEN to her boyfriend when she became frightened or they had sex. She would have been able to learn to recognize people by voice instead of face. She would have known the difference between the good guys and bad guys very easily by voice and body style alone. That is what killed it for me in this movie.