“People who grin all the time, you never know what they’re up to,” says a friend of beer-guzzling, porn-watching, hardcore-show-attending, wheelchair-bound Sumida-san (severely handicapped actor Sumida Masakiyo), whose loneliness and repressed rage are about to detonate. Japanese writer-director Gô Shibata’s self-described concept of “a handicapped Taxi Driver” subverts the adversity-triumphing disabled character but fails to convey how a seemingly simple man could suddenly become a mass murderer. Shibata’s film is best accepted as black-humored artsploitation, as when a student caregiver (and unknowing object of Sumida-san’s erotic fantasies) asks whether our antihero ever wanted to be normal (his reply, communicated through a phonetic, Stephen Hawking–like device: “I will kill you”). Cult-classically stylized in low-lit, techno-stuttering DV monochromatics that pixilate and distort as if the film shared blood with Tetsuo: The Iron Man, Late Bloomer is strangest for genuinely empathizing with the monstrous Sumida-san as though he were the typical disabled lead in an inspirational heartstring-tugger.