Time Out says
Andrés Muschietti’s three-minute fright flick 'Mamá' (2008) fully delivered on the horror of its premise: Two young sisters try to sneak out of their house when an undead specter comes to collect them. Though uneven as a whole, the first-time feature director’s expansion of the short is leagues better than its marketing suggests. After seemingly fending for themselves for five years, the feral Victoria (Megan Charpentier) and Lilly (Isabelle Nélisse) are sent to live with their uncle, Lucas (Nikolaj Coster-Waldau), and his metalhead girlfriend, Annabel (Jessica Chastain), in an upscale house paid for by the local psychiatric hospital. But the girls have brought someone along with them, a jealously protective wraith who will stop at nothing to keep the siblings close to her.
As in the short, Muschietti displays a refreshingly keen visual sense rare in modern horror movies; one gorgeous extended wide shot captures the sisters having a gravity-defying playdate while an oblivious Annabel does household chores. The co-writer-director is also well attuned to the story’s devastating emotional undercurrents, especially when the maternal allegiances of the attached-at-the-hip siblings diverge. Too bad that there’s a preponderance of idiotic plotting to make sure that certain people end up in certain places so that the jump-scares can commence. Expertly conjured atmosphere only gets Muschietti so far, but there’s enough genuine promise here that you’re willing to cut this talented newcomer some slack.