Break Blade Movie 3: Kyoujin no Ato keeps the steady pace of development from the first two movies, and takes a decidedly more mature approach that I expected. Don't get me wrong, it is still shounen/mecha. It doesn't try to get darker for the sake of cheap "depth", and it helps expand on why the situation is dramatic. Instead, the narrative is surprisingly measured and gives a more realistic feel.
As the story continues, it expands on the nature of war. The fact that a lot of it is just waiting around, that the impact they have forces characters to grow, and that there is a huge range of people that answer to the definition of "soldier", and plenty of them are not happy with what they have to do. What really makes the story get interesting is the fact that there are implications for the choices people make. The political aspect continues to lurk in the background, and the main character is forced to adapt to what he does. All in all, surprisingly mature writing for the genre.
I have to say that the animation dropped the ball in a few scenes in Break Blade Movie 3: Kyoujin no Ato. The lack of motion in favor of still shots gets more than annoying for a few scenes. The music somewhat compensates for this, but overall, the artwork feels less cinematic and more standardized in this movie. And yet, it is done well, and the backgrounds are still a wonder to behold at times.
Overall, Break Blade Movie 3: Kyoujin no Ato carries on with the style of advancement from the prior movie. The fifty minute (forty five without credits) allows to have more wriggle room as to balancing character development, plot, and action. This is used well, and gives the show a feeling of intelligence it doesn't quite deserve.