The man in the short that this was based on is separated into two people - Karen Gillan and Brenton Thwaites. Karen most notably was Amy Pond in several seasons of Doctor Who and more recently was Nebula in Guardians of the Galaxy. She tries to do an American accent in this movie, and she does a fairly good job. Only the slightest of hints around some of the consonants belie her Scottish roots. Her character comes across as overly harsh and analytical, even though she also appears to not adapt to growing concerns about her own danger.
Brenton Thwaites is supposed to be the level-headed, realistic person here, and he was just recently declared sane enough for society to leave the institution for the mentally divergent. As this is a horror movie, and supernatural things have to be real, the audience never really buys into his version of reality or the reasonable way he is thinking. As an actor, he may not have been the right choice. He is supposed to be one of the focal points, but I just watched the movie, and I'm pretty sure I couldn't pick him out of a lineup.
I was surprised to see Katee Sackhoff in this film - especially with red hair. Even though I've seen her in Riddick, I always seem to refer to her as Starbuck from her role in the Battlestar Galactica reboot. It must have been hard to act through the makeup that made her look absolutely bat-crap nutty. She's supposed to be the mother of the two siblings in what turned out to be fairly significant flashbacks. The problem is that we never really get a maternal vibe from her - there is all kinds of setup for a disagreement between her and their father, and they never establish a maternal bond.
The kids in the flashback do a good enough job - but they are kids playing in a grown up movie. There are times when you see them huddled together that you can't help but think that the director just shouted "act scared" at them right before they got into the closet or under the bed or wherever they were trying to hide.
On the whole, the movie was decent enough. I hadn't really expected much once I saw the WWE logo at the beginning except for the one thing that I didn't wind up seeing - a pro wrestler who had few lines and still couldn't act through them. Who knows? Inexpensive horror with recognizable B-list stars might be the sweet spot for their movie making.
Direction was decent, but the all-too-frequent flashbacks could have been done better
Acting was generally good enough
Effects were pretty good
Story was essentially good
Dialogue was a bit weak.
2.25/5