This film does a lot of things right. While there's a jump scare or two, the fear mostly consists of atmosphere and situations that would easily scare anyone in a similar setting. That's the right way to do horror, with the idea of something inspiring dread as opposed to cheap reaction scares that are only effective due to loud noises. It even starts out with an impossible decision that effortlessly hooks you in. Additionally, there's always something to focus on that consistently engages the audience. Shown, not immediately explained. Seen and not described. This results in mystery and guesswork that will keep you interested throughout. All in all an entertaining film, and the acting skill displayed by the entire cast is competent and fitting.
I only have two complaints. The first is that the motivation of some characters are basically nonsensical. It could be argued these people are essentially psychopaths, but even so their choices are far too extreme to be believed. Absolutely ridiculous. The second is the ending scene. I can't elaborate without spoilers, but while the concept is very cool, the execution was pretty weak. None of this ruined my overall enjoyment of the film, but there is no lasting impression because of it, which is a shame.