We've all heard stories of kids found in the woods raised by animals and that's loosely the basis for how the Muschiettis expand their simplistic short film into something classier than the current wave of horror films, something more in line with other Del Toro productions. The film's prologue and Mama's origin creates something that's more than just a haunted house movie although physically, "Mama" falls into the Japanese ghost territory of "The Ring," "The Grudge," et al. - long scraggly hair and movement as if every bone in her stick-thin body has been shattered and reassembled. This ever-present creature is brought to life by the efforts of creature performer Javier Botet (of "REC" fame) that's enhanced with CG that's sometimes very effective and other times feels like it's trying too hard.
Oftentimes, the credibility of any supernatural situation in a horror film is dependent on having actors who can make the rest of it feel real, and the Muschiettis' good timing at getting a super-hot Oscar-nominated actress like Chastain pays off, as does casting Coster-Waldau, although he's out of the equation for a good portion of the film. On the other hand, the young actress paying the younger daughter Lilly often steals scenes with her quirky behavior, crawling around on fours and playing with and sometimes eating bugs. She's quite a find because many times she's even creepier than Mama while also bringing a welcome sense of humor to the film.
Unfortunately, the more times we see any iteration of any horror sub-genre the less likely it's going to feel original and try as it may, "Mama" sometimes suffers whenever it tries to set up scares we've experienced in other movies. This is especially true when the psychiatrist more interested in the girls as a case study than for their own well-being heads towards being "Mama fodder," which is done in a way we've seen in far too many other films. By using such an overused horror cliché it takes from the originality the premise.
What keeps "Mama" tipping over into the ever-filling pit of awful Hollywood horror movies is the talent both in front and behind the camera, particularly Muschietti who creates a lush film with solid production values with evocative production design and a mix of CG and practical FX that proves him to be a fine new horror talent.
We eventually learn Mama's backstory and why she's following these girls around, but that doesn't feel nearly as novel or clever as the set up. While some may not be into the ending, I felt it was where things returned to more original territory.
"Mama" benefits from a better than average horror premise and some clever bits, and that's often enough to make up for the more obvious moments that foray into cliché territory. Either way, the talented Muschiettis provide enough creepy fun so we can forgive some of the less original ideas and "Mama" never leaves you feeling like your time is being wasted, which is so often the case these days.