James Gunn has made a career out of telling the outcast’s story. From his early films that went under the radar — the 2006 sci-fi horror comedy Slither and his 2010 maiden superhero movie Super — to his much-celebrated Marvel franchise Guardians of the Galaxy and DC debut The Suicide Squad, Gunn has even infiltrated the saturated superhero universes with oddball energy and subversive quirks. Who else could take America’s favourite superhero and turn him into an outcast, an outsider, an “immigrant,” as he put it. In fact, the first time Superman is addressed in Gunn’s iteration, he’s referred to...