For the sake of analyzing Mamoru Hosoda's storytelling style and hopefully getting some of it to rub off on me, I've watched his Digimon movies several times now. While Digimon Adventure (first movie) consistently reaffirms how masterfully constructed it is, Our War Game feels more problematic. In particular, most of the characters don't behave like themselves.
It's very odd for Agumon to say “You saved the digital world. Now it's our turn to help you,” since the children and the Digimon worked together to save both worlds. The Vamdemon arc was dedicated specifically to saving the real world.
Through the whole series, Koushiro has been shown to focus intensely on whatever task he's set for himself, even to the point of ignoring other more important things. In Our War Game, while Diablomon is attacking, Koushiro drinks too much tea, checks his e-mail, and helps Taichi's mother make a cake.
Taichi even ends up starting a fight with Koushiro for not staying on task and Yamato has to tell Taichi to lay off. After all the fights Yamato started with Taichi, this feels completely backwards.
Sora has never seemed like the sort of person to hold a grudge over something small. In Our War Game, she acts like Mimi. While I'll accept that people do get offended over unexpected things, this constitutes the entirety of her character in Our War Game. She doesn't say or do anything in the movie that doesn't have to do with her being upset over getting a hairpin.
If Taichi told Hikari to come home over something important, she wouldn't stay at a birthday party and play cards. Taichi wouldn't skirt around the facts, either: he'd tell her there's a Digimon-related emergency and she'd come right away. Hikari's case feels especially egregious because Mamoru Hosoda created her for the first movie and directed the episode she first appeared in, yet she comes across as inconsistent in Our War Game.
I'm usually able to accept inconsistencies of this sort ("Oh well, the Simpsons now aren't the same characters they used to be; the show's just jumped the shark"), but it's particuarly frustrating on this occasion because Our War Game is better than the Digimon Adventure TV series in every regard. But Hosoda's always worked with the elements of Digimon he's wanted to and discarded or reappropriated the rest, and while that allows the movies to work much better as stand-alone works, it makes appreciating Our War Game as a part of the whole difficult.
"Today?... hmm... today... right... Um... I'm just gonna wing it." -Guess who