Starts of so well but then loses steam just over the half way mark. The first half of the movie is genuinely tense. It does what a good horror movie should: rely on slow burning tension and not showing you anything concrete, letting your imagination fill in the blanks. However, about half way through, there is a sudden genre shift. The movie turns into a drama, and not a good one at that (see Tales From the Loop for good sci fi drama). The "twist" is neither cleaver or profound and doesn't really make sense. Not in a terrifyingly mysterious or open to interpretation way, but in a "why would these beings come so far to get involved in this? That's so dumb" way. We get a half assed "they are aliens so we'll never understand their motives" explanation from one of the characters but it just comes across as lazy writing. I think this film is a good argument for why no one person should be both the writer, director and editor of a movie. There needs to be an impartial third party to say "this is dumb" or "how about this instead".
TLDR: great cinematography, music and acting and excellent tension in the first half of the film but let down by a poor final act and contrived "twist".