Take a couple of parents in mid life crisis, caught in the middle of an unknown and hinted at but not explained event (Think The Happening) that makes parents attack their children.
Its dark and disturbing but it rolls along dragging the separate members of a typical family together through the unfolding event for an epic and at times darkly entertaining confrontation.
A lot of the horror / gore is inferred, through shadow play and last second cut aways, but there are some scenes that will definitely disturb (you'll see those coming) and Nicholas Cage is at his over the top egomaniacal screeching best.
If you like thought provoking films, if you like B movie horror and if you like Nicholas Cage doing only what he can do so well, then give it a watch as it's well worth it.
Well worth a watch if you're a fan 7/10
Please note - Without giving too big a spoiler, other reviewers should watch a whole film before delivering a review and assuming what happens to some of the characters.