It has been awhile since I watched it, so please excuse me if I am not completely detailed.
The anime's first 3-4 videos are quite basic for an anime. At which point was was expecting around a mediocre traditional anime with young people here, slightly off personalities and character habits.
But eventually I quickly acquired interest into the characters, their relationship, and past. The characters themselves developed as the story continued with some evolving to better fit their new world, and others acquiring a new skills, but while mostly staying true to their old self.
I love how the anime has an abundance, each with their own interests, skills, and personalities. Because of that we sometimes reach points where they have opposing ideas on how to move forward.