The years of 1965 and 1966 saw an anti-communist purge sweep through Indonesia, resulting in the overthrow of the country’s communist political party (headed by its first President, Sukarno) and the deaths of an estimated 500,000 people. More than forty years later, American-born documentary filmmaker Joshua Oppenheimer shot a movie about that atrocity’s participants, called The Act of Killing, a frequently disturbing, occasionally bizarre, and deeply compelling picture which has quickly become one of 2013’s most critically celebrated releases.

After watching the above trailer, it’s easy to understand why. The Act of Killing happens to be a real original, a daring experience that deserves the effusive praise being piled on it by critics. Oppenheimer puts the majority of his focus on Anwar Congo, one of the most notorious figures of the purge, as well as several of his friends and comrades; through the magic of cinema, Oppenheimer gives them all the opportunity to reenact their own war crimes in the style of their favorite gangster, Western, and musical films.

Of course, the clip makes it clear that some of these men don’t really view what they did as criminal, or even immoral. That sentiment alone should tell viewers exactly what to expect from The Act of Killing, though it’s difficult to fully convey its gut-wrenching complexity without giving too much away. Suffice it to say that Oppenheimer’s approach leads to some truly unsettling moments of mock-violence that carry a shocking amount of weight and feel completely genuine, no small feat in light of the film’s documentary nature.

As The Act of Killing progresses, Anwar begins drawing on his own nightmares for inspiration in the reenactments, and the film ends up taking on decidedly surrealist qualities. Its emotional impact never lessens, though, and in fact builds up the more we get to know Anwar, the people who comprise the Pancasila Youth, and Indonesia as a nation. Little wonder, then, that Werner Herzog and Errol Morris – two of the great documentarians of the day – have thrown their support behind it.

Oppenheimer’s movie has been commercially available since July courtesy of Landmark theaters in New York, Los Angeles, and Washington, DC, but come August, The Act of Killing will receive a bigger (but still limited) theatrical push across the States. If this sounds like your cup of tea, check here to see when the film will arrive in your area, and make sure you check it out if you get the chance.

The Act of Killing will hit theaters across the States