An entertaining, thought provoking and at times truly scary first film. It reminds me of early DePalma, both in it's strengths and weaknesses.
In his first feature, Amenabar uses violence and fear as means to explore deeper themes and psychology - in this case the way we're all drawn to violent images, even if we claim not to be. But these ideas stay pretty heady, and at times teeter on preachy or obvious. The film is full of wonderfully clever visual and sound techniques, but occasionally you become so aware of the flash and `hey, what a cool way to film a scene' that it takes you out of the movie. Also for me, the score is a little too obvious a Bernard Herrman homage.
It also goes on a little long. The first 75 minutes or so seemed downright brilliant, but when you drag a thriller out, often the creakiness of the plot shows through. In the end there are a few twists too many for credibility, and it crosses into, `c'mon, she would have gone to the cops by now' territory for the last half hour.
Yet, even once it starts to feel a bit silly, it's never dull, and the tension stays high. For all its flaws, it scared me and it got me to think, and that's always worth applauding.