In a post-apocalyptic future, where 800 million people lead marginal lives in what used to be the Northeastern United States, the only representatives of law and order are a small cadre of paramilitary “judges” apprehending perps and, when necessary, dispensing summary justice on the spot. Two such judges, the seasoned Dredd (Karl Urban) and the rookie psychic Anderson (Olivia Thirlby) find themselves trapped in a 200-story high-rise and hunted by a ruthless gang leader (Lena Headey). The 1980s sci-fi comic-book hero gets his second movie treatment (there was a Sylvester Stallone campfest in 1995), courtesy of writer Alex Garland and director Pete Travis. It’s suitably grimy and relentlessly violent. Urban does a fairly witty Dirty Harry impression, and the results will probably satisfy the comic’s remaining fans.