The twist at the start is excellent, and so unexpected which hooks the audience. The protagonist is portrayed as some cold and calculated serial killer, but for sake of the story, she goes onto make serious amateur mistakes that make the whole thing seem unrealistic. One error fair enough, but it is just a catalogue of stupidity after her character has been developed with serious merit. Secondly, the victim makes catastrophic errors too which plays an integral part in propelling the ramboesque fighting to continue longer than necessary, I'm assuming in the hope it is perceived as suspense. Consequently, some scenes are very predictable.To conclude, with the initial plot, this movie had a lot of potential to be an all time great like Calibre, or the invitation. But the producer treats the audience like a child at times and its frustrating. It's 3 stars due the initial twist, and some great acting by the protagonist.