
With ‘Chappie’ Frankenstein’s monster gets a titanium makeover in a science-fiction blood-spurter and would-be heart-warmer that wavers uncertainly between laughter and tears. Set in South Africa in the usual bleak future — yet again, it’s man against man, as well as machine — the movie imagines a scenario in which tin-can police march in lock step with their human analogues to roust the usual tattooed and dreadlocked gun-toting degenerates. All the aerial shots of the dangerously swarming and swelling multitudes suggest that such draconian tactics are necessary. The director Bloomkamp, working with a script he wrote with his wife, Terri Tatchell, doesn’t engage with the question of whether a police state is necessary; he just goes with the paramilitary flow. And, as an introductory flurry of news reports indicates, law demands order. To help stem the murderous tide, the authorities have deployed a force of armed robots, called Scouts, to serve as shields for their human brethren or to fire on the heavily fortified shouting masses. After the preliminaries, a protagonist emerges in the person of Deon , an engineer for the outfit that churns out the Scouts. His only colleagues who, at that point, seem vaguely sentient are his boss, Michelle (Sigourney Weaver), and a teeth-gnashing foe, Vincent (Hugh Jackman), who parades around with a gun on his belt. One night, Deon takes a decommissioned robot home and, after some Red Bull and energetic keyboard abuse, solves the problem of artificial intelligence. Enter Chappie, played with a singsong by Sharlto Copley, Mr. Blomkamp’s favorite attraction. Things go wrong like genre clockwork, and Chappie ends up in the hands of a troika of misfit criminals who decide that a smart robot would make a useful accessory to go with their pink and yellow guns, which look as finger-licking good as Valentine’s candy. The South African musicians Ninja (the guy) and Yo-Landi Visser (the woman), bring the cartoon charisma as the flashiest two thirds of this trio, with the American actor Jose Pablo Cantillo, as Yankie, valiantly thumping along as the third wheel. A well-greased matched set, Yo-Landi Visser and Ninja (the characters share the performers’ names), take to Chappie-rearing seriously and soon teach the robot how to talk, shoot and stroll like a gangsta while he, in turn, takes jerky baby steps and calls them Mommy and Daddy. It’s a crazy mess of a film, It’s a goof, as is so much of “Chappie” despite the violence, crenelated brows and choreographed grimaces. For all of Mr. Blomkamp’s attention to grim speculative fiction and its trappings (the despair, the gadgets), he often seems more at ease when things are going right for his characters or when he’s lobbing a joke. Sometimes he uses comedy as a distraction or to soft-pedal an emotion or an idea. It’s funny when Chappie watches the cartoon “He-Man and the Masters of the Universe,” because you see him learning, but the scene also gestures to the idea that hyperbolic masculinity is absurd learned behavior. And when Yo-Landi reads a children’s book or chatters sweetly to Chappie, something rather more surprising happens because Mr. Blomkamp has let real emotions creep in, too. This is Mr. Blomkamp’s third feature, and he’s still finding his way as a director; again and again, as in the past, he struggles with the material, a performance, an idea, the tone or just some blocking. “Chappie” is more visibly modest and less narratively ambitious than his last movie, “Elysium,” which benefited greatly from Matt Damon’s emotionally anchoring star turn as an Everyman struggling among the human-made ruins. Scaling down has its drawbacks, as some of the visible digital artifacts in “Chappie” make clear. Yet even at his shakiest, Mr. Blomkamp holds your attention with stories about characters banding together to emerge from a hell not of their own making.