In this game, you can choose from three scenarios (Al, Klinsy, and Papelne) at the start of the game. Each scenario not only has a different story, they have different exploration and battle systems. By clearing all three scenarios, a new scenario will appear.
There's still no official release date for Brave Dungeon: The Meaning of Justice, outside of a vague 2020 listing. That's the way its been for quite some time now, so hopefully we get something a bit more specific soon.