Not Great, Not Terrible.
It held my interest for the most part though because it was a Shamalan film, I did anticipate a twist which never came (I assumed the three girls would turn out to be nothing more than personalities and that the main girl who survived was behind it all due to her childhood trauma) but that twist never actually came.
Gotta say, ī think the film "Identity" was a lot better on this issue.
The ending was silly.