Do you really need a movie critic to weigh in on this one? It’s just another cynical opening-weekend-money-magnet remake, above reproach only for delivering so straightforwardly on the promise, if you can call it that, of its trailer. A comely adolescent girl (Camilla Belle) spends an evening alone in a swanky isolated house without light-switches or cell-phone reception, pouting over boyfriend troubles, sucking on a Popsicle, and — inevitably, I’m sure — fielding phone calls from a heavy-breathing psychopath. Having abstained from character development and stalling for something to do between calls, the movie dwells in the house’s dark corners, plugging plot holes with overzealous sound design and leaving viewers to wonder if maybe it is a social-message picture after all: Babysitters, we will learn tonight, don’t get paid enough. Should they unionize? Even the live-in housekeeper knows better than to take that gig; her reward is a formidable severance package.