Recipient of rapturous early support from godhead documentarians Errol Morris and Werner Herzog (who both signed on as executive producers), Joshua Oppenheimer's The Act of Killing is a shape-shifting documentary exploring the horrifying history of Indonesia, where government-approved paramilitary organizations exterminated between 500,000 and a million "Communist dissidents" over a single year. The year was 1965, which means when Joshua Oppenheimer took his camera to Indonesia in the early oughts, he found a good number of former executioners alive and well and happy to talk about their role in "the crushing of the Communists."

How you feel about watching unrepentant killers boast about their bloodletting will determine how you feel about the first 90 minutes of this film. Seeing an affable grandfather demonstrate the blood-splatter-reducing method of garroting he used to kill hundreds of men, then break into a soft-shoe cha-cha, made me want to vomit. So did another killer's placid recollection of a day spent fatally stabbing every Chinese person he saw on the street. The government that supported these killings remains in power, and members of the 1965 execution squads are cultural heroes to this day. Any and all remorse the killers will ever feel will come from their own consciences; yet, with the full support of their nation, it seems unlikely that these men will ever experience a proper dark night of the soul.

Which brings us to The Act of Killing's most audacious component. Not content to have killers describe their killings, Oppenheimer invites his subjects to reenact their "greatest hits," complete with supplementary actors, respectable production values, and bloody special effects. Each of these scenes is deeply upsetting and would be unforgivable if it weren't for the supplementary fallout. After reenacting the role of one of his victims, our killer grandfather is left visibly, pathetically shaken. In the end, while revisiting the site of his major killings, he's literally left gagging, unable to stomach what he allowed himself to become. It's a tiny moment of justice. Then he goes home to his loving family.