“Darkness Reigns” (** out of four) was a not-bad horror thriller about an amateur film crew (Ford Fanter, Jennifer Wenger, Zachary Mooren, and others) whose film set is ravaged by an unseen demon who is seeking vengeance for a past deal they made that promised them fame and fortune. Casper Van Dien is amusingly cast as himself as an actor starring in their low-budget project. Film gets going after a slow start and has a sufficient amount of scares and jolts but is too derivative of “The Exorcist” and “Alien” to really make a mark. Still, better than most of its kind and better than “Exorcist” sequels.