I got to see this film at a special screening at the Alliance France in Manila, the French embassy's cultural center. Many of the small audience in the screening room (the copy screened was a DVD) did not bother to finish the film.<br /><br />For myself, I found the film a flawed but powerful experience. One major flaw is, as other reviewers have pointed out, its cold opening. In other words, it assumes you already know what S-21 is and what the Khmer Rouge are. Without this valuable background information, which the documentary does not provide, the viewers may be lost at first.<br /><br />It is also kind of dry, since the movie takes place only within the walls of S-21, involving only the few survivors of the prison and some of their former jailers. Essentially they spent the entire film talking. There is no attempt on the part of the director to make it more cinematic.<br /><br />However, the patient viewer will soon find him or herself immersed in the horrors of the Khmer Rouge as detail after detail of the atrocities committed in the prison emerge. The handful of survivors go through mementos of the prison, including logbooks detailing the tortures committed against inmates, along with some of those who worked in the prison, including a guard and a doctor. The question the survivors constantly ask their former jailers is: How? How could you do these things? And they have no answers.<br /><br />The most chilling scenes in the film involve a former prison guard recreating in an empty cell the routine he took with the prisoners, bringing them food, water or a container to pee in, threatening them with a beating if they don't go to sleep or cry too loudly. Its throughly disturbing to see, even if there are no actual prisoners there.<br /><br />S-21 is not for everybody. But if you're already familiar with the Khmer Roune and this part of Cambodian history, the documentary may be worth watching to deepen your understanding of this dark period of history.