This movie was too long as far as I am concerned. There is no real connection made with the children and the mother is so unlikeable I found myself thinking why not possess her family and wipe them out? It's probably the most interesting thing that's ever happened to them. I struggled to find even an ounce of care for anyone in the story except the grandmother, but that only happened at her death scene.
There's no character development, no real suspense, no horror aspect. As for the parts of the "horror" and possession, all the classic elements are there. Religion, crawling on the walls, child possession, speaking in tongues, holy water, etc. It feels cliche and unremarkable. Inspired by true events? Maybe, but if it is, then it's been highly edited.
Sadly, as a horror film in the demon possession genre, this one is not worth your time. It just can't compare to any of the others.