“It’s Dad. He’s got a knife.” So do many of the dads in the Midwestern town of Ogden Marsh, where men and women alike are suddenly developing blank stares and homicidal urges. The boy hiding in a closet with Mom, while Dad stalks them with that kitchen knife, is destined for an unpleasant end, in a sequence that re-creates the opening scene of George A. Romero’s 1973 film, The Crazies. For the remake, director Breck Eisner (Sahara) and screenwriters Scott Kosar and Ray Wright have kept the key elements of Romero’s scenario, including the U.S. military’s heavy-handed attempt to contain the virus it accidentally unleashed, while largely doing away with the speechifying that drags down the original (sorry, Mr. Romero). Despite a mid-film lull of his own, Eisner stages a series of nifty action sequences, nearly all of which feature a moment of surprise, as well as gruesome wit, including a memorable bit of business involving a sheriff (Timothy Olyphant) with a badly stabbed hand and a nearby crazy who must die. Although English actor Joe Anderson nearly steals the movie as the sheriff’s increasingly unhinged deputy, Olyphant grounds it with his ever-fascinating mix of soulfulness and swagger. Any day now, he’s gonna be a star.