Mama features two very creepy children, along with a host of other horror movie standards. Abandoned cabin in the woods - check. Haunting music coming through the grates - check. Scurrying things in the shadows that you can't quite make out - check. Escapee from a lunatic asylum - check. Near inability of anyone to carry a working flashlight - check. Add to that a rabid curiosity that prohibits anyone from getting a generator and hooking up floodlights before going into a house that practically screams "Enter and Die!" - check.
But here's the rub - Mama still works pretty well. You probably won't recognize Jessica Chastain in the role of Annabel at first and Megan Charpentier is a real find as Victoria, the older of the feral little girls. Mama does some very nice things within the framework of a PG-13 rating - this is far more "jump scare" than "gore scare." When first discovered after five years on their own in the woods, the kids are scary enough, but the children's crayon drawings are haunting clues into their time in the woods. The idea is that something looked after them and is continuing to do so - and it's jealous. The Mama site has some very intriguing supplemental material from the psychologist who works with (and just maybe sees his fortune in) the girls.
I found it interesting that this is a very female-centric tale. The male characters aren't evil and are a definite presence, but this movie belongs to the females, primarily the two little girls and the two mama-figures, only one of whom starts off wanting the children. (But keep your eye on the public records woman - she's a key part of the film as well - and the Ark of the Covenant is probably somewhere on Aisle 17!)
Also, here's something just for fun. The cabin is the scene of any number of horrors and I kept thinking, "They're never going to sell that place." Did you know that, in at least one case, the sale of a house was rescinded because the house was found to be haunted - as a matter of law?? Sure enough - some things you just have to reveal to a prospective buyer - malevolent spirits are about the same, legally speaking, as a case of termite damage. Only, you know, more willing to kill you outright.