I’m told that Joseph Gordon-Levitt’s 2009 short, “Sparks,” based on Elmore Leonard’s brilliant short story of cat-and-mouse-as-dialogue, is terrific and sharply cast. Gordon-Levitt’s feature debut, “Don Jon,” (The Landmark, Laemmle NoHo 7, Laemmle Claremont 5) lacks a writer of Leonard’s mastery (because the director made the mistake of writing his own script) but confirms that ...