End of an era. I felt such a profound loss at Capaldi's leaving that I actually didn't watch this when it aired because I thought I'd be inconsolable. Fortunately, his farewell speech goes on for five-and-a-half hours so I was over it by the end, but I still think this was a wonderful end to one of the very best ever Doctors. The 60s fan in me yearned to see more made of Ben and Polly, but they would have been superfluous to the story, and lamentable and unnecessary recastings. I like the idea of Testimony, but the best element of this is the "Doctor of War" storyline, against the backdrop of the Christmas truce. A brilliant moment in a brilliant episode.