I just saw it at a 4:00pm show in Auburn, AL. For whatever reason they released it again at a number of AMC theaters for one day only. There were maybe 12 of us at this showing.
It is well worth seeing. There is a 30 minute show immediately following the main film which gave a lot of the technical background. What Con was talking about was in that.
The movie has no historians, academics etc.... It focuses only on WW1 ground combat on the Western Front with UK troops. There is no discussion of strategy and very little about tactics. There is not any real story line to speak of, other than what a person in ground warfare would experience from recruiting through the armistice. Almost all of the dialogue was from recorded interviews done in the 1960s and 1970s - so the voices were of survivors.
It was very good, I've never seen a war documentary quite like this one. They did a wonderful job adding voice material to silent B/W footage. They colorized some of the stuff - but it was really well done (the technical 30 minutes at the end explained what they did).