When Neill Blomkamp burst onto the scene in 2009 with his blisteringly brilliant debut film District 9, he brought someone else with him: actor Sharlto Copley, whose entirely improvised performance as nebbish bureaucrat-turned-freedom fighter Wikus van der Merwe immediately marked him as a talent to watch.

Sadly, much like Blomkamp, in the eyes of many Copley has never been able to make the same magic happen twice. Many saw Elysium (and Copley’s performance in it as an unhinged hitman) as a massive letdown. And then there was Chappie. Currently sitting on a 32% approval rating at Rotten Tomatoes, it was widely panned by critics, with many singling out Copley’s eponymous character as one of the film’s main problems. David Edelstein of Vulture went so far as to describe the movie as “Robocop starring Jar Jar Binks.” But look past the bunny ears and the admittedly grating South African accent, and there are deeper layers to the performance that elevate the entire movie when the writing threatens to bring it crashing down.

Chappie

Courtesy of: Columbia Pictures

For those who don’t remember the plot of Chappie, here’s a quick refresher course: it’s half past the future and Johannesburg is being policed by a series of automated drones that have brought crime rates tumbling. Deon (Dev Patel) is a developer who successfully creates a prototype artificial intelligence and downloads it into one of the robots, which is promptly stolen by gangsters Ninja and Yolandi (of real-life South African rap group Die Antwoord). The newly-conscious robot is christened Chappie, covered in bling and taught how to commit crimes. And then the ED-209 turns up.

Chappie is a tabula rasa – a blank slate. His creator sees him as the next step in human evolution; his adoptive gangster parents see him as an accessory they can mold in their image. The central theme of nature versus nurture is presented about as subtly as a sledgehammer to the face, but Copley sells the hell out of it. The actor was actually present on set to provide a reference for the effects department, and his performance is as impressive as anything Andy Serkis has given us in his career – more so, even. Serkis had hundreds of dots on his face, capturing every tic and micro-expression. Chappie has no face; just pixels for eyes and a pair of swivelling antennae, so everything must be conveyed through voice and gestures.

Those who described Copley’s performance as jarring were missing the entire point of it. The best comparison isn’t with Jar Jar Binks, but with Jack – the bizarre 1996 Francis Ford Coppola joint starring Robin Williams. But where Williams played a 10 year-old stuck in a rapidly aging body, it’s Chappie’s mind that develops almost too quickly to keep up.

It’s difficult to convey aging when your character doesn’t even have a proper face, but Copley manages to convey Chappie’s intellectual development in a dozen subtle ways. There’s the way his patterns of speech change over time, from short staccato sentences to longer, more eloquent phrases. His voice even “breaks”, dropping in pitch by around half an octave as Chappie reaches “maturity”.  His bearing changes, too. In the moments after his birth he is visibly terrified, trying to draw into himself as much as possible. By the final act he has developed a trademark swagger, invisible pants hanging off his backside, and an habitual sniff picked up from one of the gang members. Robot see, robot do.

More often than not this is all played for laughs, as Chappie breaks his friends’ knuckles with over-enthusiastic fistbumps and scrambles his swearwords (“fuckamotha” seriously needs to make it into the dictionary). But Copley also tugs at the heartstrings, too. As an early trial by fire, Ninja drives Chappie out into the rough part of Joburg and leaves him to make his own way home. The pleading in his voice – “Chappie wants to get in… please can I go in the car?” – is every bit as haunting as David’s abandonment in AI: Artificial Intelligence, and takes on a much darker tone when he finally returns home, one arm missing, and tells his mother about the “man with a van” who tried to kidnap him.

Sharlto Copley’s performance in Chappie is not a subtle one, because Chappie is not a subtle film. But a lack of subtlety is what makes Blomkamp’s movies – and Copley’s performances – great; they’re proof that bombast and intelligence are not mutually exclusive. In District 9 Copley played a man who discovers his humanity as he is transformed into something increasingly less human, and Chappie sees the actor take that theme to its logical conclusion: a robot who first becomes human, then so much more.