Maybe because of my advanced years I tend to be a little bit harder to please when it comes to horror, shocks, etc. I have seen so many 'scary' films I find it harder and harder to be made to sit on the edge of my seat.
There is no point in trying to add to previous reviews in terms of storyline etc., so all I will say is.....this is a very tense film, there are some comical moments, the acting is good, you do get attached to the characters....and yes it is a bit unbelievable at times, but it did have me on the edge on my seat, so just enjoy it.
Sometimes it's good to set your mind free, forget about logical, believable story lines, and just enjoy a good film. This IS a good film. Give it a try.