Another useful guide, in case you ever find yourself in a remote cabin in the dark forest with a bunch of your 20-something friends, gathered to wean one of your buddies off of a nasty substance-abuse habit: if you find an ancient book, bound in human skin, written in human blood, amidst a bunch of sacrificial animals, do not start reading it out loud. In fact, maybe you should just get in your car and drive until you find a Holiday Inn or something.
Needless to say, the young folks in this movie do not follow this advice. Instead, they (and their dog) find themselves visited with all sorts of horrors. (MPAA sez: "strong bloody violence and gore" and that's kind of an understatement.)
Jane Levy, who I like as Tessa in the TV show Suburgatory, plays the primary character here, saying and doing things that will not appear on primetime broadcast TV anytime soon. (The rest of the cast are generically pretty actors and actresses who aren't asked to do much besides scream and die.)
It's actually a remake of Sam Raimi's cheapie made in 1981 with Bruce Campbell. I dimly remember seeing it, but the IMDB raters have it a full point better than this effort.