In a rather interesting twist, Peter Jackson (the man best known for either his shlocky horror or huge blockbusters films) turned in a documentary focusing on World War I. There have been hundreds of those already and it's fair to wonder where the added value of this documentary lies, but it wouldn't be Jackson without a trick or two up his sleeve.
The big sell here is the restored footage. We're so used to seeing crummy, sped up black and white footage of the past that it's almost a shock to see real, historical footage in full color and without all the jittery decay. It's a nice reminder that our history was actually in color instead of grainy black and white.
While this restored footage is impressive, it's not there for the entire runtime and the rest of the documentary is made up of personal recollections on top of regular black and while historic recordings. While impressive in its own right, I've heard these stories so many times before that they do feel somewhat superfluous. This would've been better if it was half the length.