This is how you tell a story. It has good frights because you're not expecting them. It has a good story to tell because you go in thinking you know. Then they tell you the truth and you lose respect for the main characters, but then end up feeling for them! Wow
Also, this is how you can have a strong female character along a strong male. There's strength in being a woman rather than her being like a man. Both actors acted their tails of in this one.