"The Missing Picture" is a very unusual documentary and was nominated for the Oscar for Best Foreign Language Film. It's so unusual because filmmaker Rithy Panh tells the story both with archival footage AND little figurines that he created for the film! Perhaps this was a way to make the horror of the Khmer Rouge easier for the audience to watch, as an hour and a half of footage of atrocities would be just about unwatchable considering how brutal this regime was. And, since you don't see live actors in the film-- just narration and film clips, seeing it in its original French language or the optional English language form is a roughly identical experience, or at least I assume so.
While I enjoyed how unique this film was and figure its uniqueness probably led to its Oscar nomination, I must confess that the narration made an exciting story very, very slow and a bit tedious. Perhaps the French language version is better, I don't know. All I know is that a film like "The Killing Fields" or a regular documentary about the subject is something I could have enjoyed or at least stuck with better.