The Fear Factor-ish Open Water was a smash hit at the last Sundance Film Festival, and judging by the film’s marketing campaign, distributor Lions Gate would have us believe that it’s the second coming of the Blair Witch. “Based on a true story” (not exactly, but you’ll have to see the film in order to figure out why), Chris Kentis’s cruddy-looking feature observes what happens when a dive boat leaves a young married couple, Daniel and Susan (Daniel Travis and Blanchard Ryan), stranded in the middle of the ocean, forcing them to contend with Mother Nature and her sea-dwelling minions over the course of many hours. Before boarding the plane, Daniel and Susan talk to each other on their cellphones, check their e-mail, and assure each other that their vacation resort has an Internet dial-up. Yeah, they’re yuppies all right, and Kentis means to put them in a place where their modern comforts can’t help them. First and foremost an experiment in terror, Open Water also functions as a study of the failure of communication. Though Daniel and Susan barely register as characters, it’s clear that something sinister lurks beneath the surface of their seemingly happy domesticity. The night before their disastrous scuba-diving excursion, an intimate, horned-up conversation suggests a couple that has built a relationship out of making compromises. A day later, a shark takes a small bite out of Susan’s leg and the couple begins to sort through whatever baggage they’ve left unresolved between them. Their bickering may sound authentic, but considering that there’s no couch in sight for Daniel to sleep on after they’re done blaming each other, it doesn’t exactly fit the mood. For anyone who’s watched Jaws one too many times or, like Daniel, lives for shark specials on the Discovery Channel, the relatively pint-sized fish that gather around the couple aren’t exactly scary. Luckily, though, the sea (not to mention a revealing thunderstorm) is sinister enough, and while Open Water may look like shit, the crummy DV used for the film has a way of degrading the surface of the moving water so that it becomes difficult to distinguish the peak of a small wave from the fin of a shark. When Susan wonders if it’s scarier seeing or not seeing the sharks around them, she may as well be appealing to the audience. You decide.