Backed by Western governments, the paramilitary groups and preman gangsters responsible for the massacres, the biggest being the Pancasila Youth, gained power in Indonesia.

The Pancasila Youth openly brag about their role in the massacres on television and express their intention to further curb the spread of "neocommunism" and far-leftism in Indonesia, and is backed by high-ranking government members, including then-vice president Jusuf Kalla.

Ibrahim Sinik and Soduaon Siregar, journalists of Medan Pos who covered the genocide, show support but deny direct participation.

Koto runs in the 2009 Indonesian legislative election as a candidate from the Workers and Employers Party intending to extort locals once in office, but is easily defeated.

Many high-ranking government officials are also leaders of Pancasila Youth factions, allowing them to commit corruption, rig elections, and clear land for developers.

During the re-enactments, titled Arsan dan Aminah, some of the gangsters including Zulkadry express caution so as to not potentially destroy their reputation as heroes.

The Act of Killing came to be when Oppenheimer and co-director Christine Cynn went to a Belgian-owned palm plantation nearby Medan, where the female workers were asked to spray the plant killer herbicide to their body; the film that came out of it, The Globalisation Tapes (2003), documents their worries on making a union against the system because their grandparents were alleged pro-communists killed during the genocide.

Starting in late 2004 with the help of death squad leader Amir Hasan, they were able to contact many of his kind, moving up the ranks of those involved, including retired military officers in capital city Jakarta and two retired officers of the Central Intelligence Agency in the United States, and met Congo in Medan in 2005 as his 41st interviewee.

[6][7] Oppenheimer handled half of the cinematography,[10] with Lars Kree, Carlos Arango de Montis, and the Indonesian co-director doing the rest.

[7] Filmed in 2009,[11] the re-enactments were funded by the filmmakers, but some scenes were made by Congo's squad, with production values Oppenheimer called "awful".

The sound was edited at the soap opera studio of TVRI, Indonesia's state television network also dominated by gangsters.

[6] They also frequently delivered dailies and transcripts of it to National Human Rights Commissioner Stanley Prasetyo, who helped with interview ideas.

Oppenheimer's vision for the film changed with his arrival, who openly condemned the killings but also expressed caution on the re-enactment's potential in reshaping Indonesian history.

It stemmed from a re-enactment where Congo mutilates a teddy bear symbolizing a girl, then telling Koto, "you tried to bribe me with your daughter.

At an airport in London, another executive producer André Singer directed Oppenheimer to Herzog, whom he has also worked with, to preview eight minutes of the film; he immediately displayed interest.

He then agreed on the trimming, but assisted editing so as to not remove crucial elements (he marked scenes by three levels of importance), and analyzed three or four rough cuts with Oppenheimer.

[16] The editing team was led by Niels Pagh Andersen, accompanied by Charlotte Munch Bengtsen, Ariadna Fatjó-Vilas Mestre, Janus Billeskov Jansen, and Mariko Montpetit,[7] using the software Final Cut Pro.

[15] The Indonesian co-director noted that his fellow filmmaker friend was once questioned by a state official, who admitted making efforts to try uncover his identity.

Oppenheimer stated that despite lamenting how the shorter cuts meant less character depth, he wanted the film's contents to be seen by Western audiences: "What cinemas are going to take a 2-hour-and-40-minute experimental documentary about genocide in Indonesia that no one's ever heard about?"

The film premiered in the country, screened by the National Commission on Human Rights (Komnas HAM) throughout late 2012 for filmmakers, authors, advocates, educators, and organizations for the genocide survivors.

The positive reception prompted the assembly of a campaign team by some of them in collaboration with the film's production company Final Cut for Real on behalf of Partisipasi Indonesia.

[29] On 10 December, coinciding Human Rights Day, screenings were held in at least 50 venues across 30 cities, with an estimated 30 to 600 audiences per theatre.

The only screening that stopped midway was in Central Java upon police demand; another close call was committed by paramilitary groups.

When a news editor published an article titled "World Condemns Pancasila Youth", 500 members of the gang stormed the office and beat up the general manager.

The website's consensus reads, "Raw, terrifying, and painfully difficult to watch, The Act of Killing offers a haunting testament to the edifying, confrontational power of documentary cinema.

"[41] Australian National University Professor of Asian History and Politics Robert Cribb stated that the film lacks historical context.

[42] In reply, Oppenheimer said that "the film is essentially not about what happened in 1965, but rather about a regime in which genocide has, paradoxically, been effaced [yet] celebrated – in order to keep the survivors terrified, the public brainwashed, and the perpetrators able to live with themselves...

"[43] Bradley Simpson, historian at the University of Connecticut and director of the Indonesia/East Timor Documentation Project at the National Security Archive, states the "brilliant Oscar-nominated film" has prompted vigorous debate among Indonesians about the crimes and the need to hold responsible parties accountable, and suggests that it could have a similar effect in the United States, whose own role in the killings "has never officially been acknowledged, much less accounted for, though some of the relevant documents have been made available to the public.

"[44] An Indonesian academic, Soe Tjen Marching, analyzed the film in relation to Hannah Arendt's theory of the banality of evil.

[46] A subsequent interview on Al Jazeera's program 101 East revealed that Anwar had misgivings about the film and the negative reaction to it in Indonesia, which was causing problems for him.