It had been a long time since I have seen such a well rounded thriller, where motives are not cliché and predictive. The acting jives extremely well with the dialog (albeit I watched with sub-titles) and the actors were awesome.
The mother's acting was so realistic that in empathizing with her, a layer of understanding is added to the storyline. The story neatly makes a subtle point about the similarity in human motives, and how where you stand in relation to it, determines your perception.
The use of time is very interesting in this movie, like an origami. It starts as a plain paper (linear), but takes on elaborate form. There are a couple of movies where this technique has been used, but in this case, the time/origami texture is seamless.
I am sure the above description might sound abstract and arcane, but if you watch the movie, you will understand what I mean. :)
A gripping and intelligent thriller, a must see.