With "Deadpool 2," which is a running commentary on its own sardonic self, it helps to have a high tolerance for superhero genre. Deadpool's constantly referring to this or that expository dialogue as "lazy writing"; Deadpool's marginal place in the "X-Men" film universe comes up for major mockery, just as Reynolds' own failed "Green Lantern" movie is a target, as it was in "Deadpool" the first. Director David Leitch, well versed in both traditional stunt work and digital fakery, worked on "John Wick," uncredited, and directed "Atomic Blonde." At its best, his flights of fancy here are crazily inspired, each swoop of physics-defying movement, every new leap from or to a speeding vehicle, delivered with twisted panache. The difference between what Leitch can do, and what director Matthew Vaughn favors in those cruddy "Kingsman" outings, for example, is the difference between violent action with a sense of humor and brutality, undisguised.