I had a good time with this one, and it helped that I didn't know anything about it going in. There's this constant sense of uneasiness and feeling that something is always around the corner. Unlike Longlegs, where I think hype didn't help, this benefits from not knowing much about the level of suspense. I say suspense because I'd call this more of a survival film with touches of horror throughout. I get why people aren't liking it, but it had some good scares, though the movie does just sort of...end.
I'll say this: between Keeper and The Monkey, Tatiana Maslany needs to ditch franchises and do more horror. She sells the dread and distress in her performance and she's easily the most memorable part of the film. I could see her having a healthy horror career if she continued down this path. I wouldn't say you need to rush to see this film in theaters, but again, I liked what I saw.