After a bit of background, we are told the chronological story of a genocide, events of 1994 in Rwanda. The focus of the story is the UN commander who was there, and unable to stop it. But it's not really about him, but about the 800,000 people who were killed, many hacked to death by machetes.
The right details are given. The interviews are excellent. There are clips (but only one of the violence, and it is seen in the distance).
10 stars. Documentaries do not get any better than this. But the subject is so real and so terrible you may not want to watch. If you watch it, you might be crying by the end.