Great film, plagued by poor reviewers.
There seems to be disconnect with a lot of the reviewers for this film so I'm going to try and clear things up.
Consider that this movie is 25% Horror, 35% Sci-Fi, and 40% Thriller. You'll now understand that the horror aspect isn't represented nearly as much and adjust your opinion accordingly. What I imagine has happened is that all of these are well meaning but confused people and not trolls who have nothing better to do with their lives. Apart from a couple of jump scares and mild scare tension it only barely qualifies in the horror genre.
It's a great film if you've seen some good Sci-Fi in your time.