Really bad dialogue, with which all the necessary (and unnecessary) backstory for characters and the movie is divulged.
Lots of people die.
Asshole boyfriend does not die.
The film is visually stunning and well-researched. Eggers put a lot of effort into making it historically accurate in design and dialogue. However, the story itself falls a little flat as there is no history or backstory to the witch (or witches) in the woods. The story itself makes you wonder if the witch is actually real or just a figment of the family's imagination and beliefs while they try to explain mishaps, but towards the end the film takes…
This review may contain spoilers. I can handle the truth.
Conceptually, the film (and the game) is fine. However, there are no real consequences shown for dropping out of Nerve or going to the police about the game. There are just "legends" from a previous rendition of the game. While the filmmakers obviously know their audience, the moralistic pull to "be careful about what you say online even though it's easy to hide behind anonymity" is so blatant that it takes away from the quality of the film.