Prop Recycling: A LOT of art assets from the first game get reused here.
What's Fumi doing in Amane's mind garden?
The portrait used for policemen has an evil grin. This made sense in the first game where the Police Brutality trope was in full effect, but makes less sense here, where the police is not portrayed as evil. What makes it more jarring is that one scenario uses this portrait to portray a wimpy character.
Reality Subtext: The plot opens with Japan getting hit with a powerful and destructive earthquake, and the damage only persists as the Septentriones invade...
Recursive Adaptation: Devil Survivor 2 The Animation is getting it's own manga adaptation, despite the fact that there was already a manga adaptation of the game.
The anime adaptation was originally meant to be a New Game+. One remnant of this draft of the story is Hibiki starting out with Byakko, which in the game would only be possible in a New Game+. Word of God also stated that if the anime was 2 cours, they'd have had Hibiki start out with weaker demons and gradually power up during the course of the story.
In the anime, Ronaldo was originally meant to survive Megrez's final attack and show up in episode 12 to face off against Yamato. However, they abandoned that idea and reduced Ronaldo's influence on the story to handing Hibiki a USB containing data relating to Yamato's plans.