It shouldn't take a doctoral degree to figure out that the “Mama” whom the children credit with raising them during those missing years isn't just some figment of their imaginations. Ominous flocks of moths, strange noises in the girls' closet and oozy black holes in the walls are telltale signs that Victoria and Lilly weren't alone and that the fierce being that watched over them has followed them to suburbia.
When a convenient coma puts Lucas in the hospital, Chastain gets to show her stuff, convincingly morphing her sullenly self-centered rocker grrrl into a protective mother figure. The child actors also give credible turns as the lost little girls trying to adapt to a more normal life.
But their performances can't quite anchor Muschietti's wildly uneven first film. Unfortunately, he counteracts moments of filmmaking brilliance — particularly, a lingering, elegantly executed shot of Annabel busily doing chores while Lilly enthusiastically plays tug-o'-war with a companion who mostly stays tantalizingly just out of frame — with examples of sheer horror movie stupidity — notably, at least two seemingly bright characters' decisions to venture into the frightening remote woods in the dead of night.
— Brandy McDonnell