This movie was way too *beep* predictable. [SPOILERS]
Seriously. I figured the ENTIRE twist out down to the very last detail as soon as she saw the "doppleganger [wink-wink]" driving down the street LAUGHING and SMILING. And the part where she follows her to her flat was even more of a dead give-away.
At least the brother survived.
It was well acted, too. And well-made. Excellently made, actually. Ah, I guess I shouldn't complain.