We have heroes from the first game, Junpei and Akane, heroes from the second game, Sigma and Phi, and 5 new (?) characters all playing 3 sided Prisoner Dilemma this time.
Playing this without at least the previous one sounds like a pretty painful idea to me. The time continuum got even more confusing, as it seems you can start solving the escape rooms in any order. The escape room mechanics and visuals are straight from the previous game. But the curscenes have improved enourmously, though.
In the previous game we had K wearing an iron mask with a lock. In this game we have Q, a kid, also wearing an iron mask, with a key code. Consider that in previous game there was a kid named Quark.
As a puzzle game, I’d say it even got worse. Easier, but also worse. There are a lot of puzzles where you need to fit pieces into a box, for example, something I rarely remember in the previous games.
Also the length of the puzzle rooms is widely different. Healing Room is very long, while some others finish before they barely begin.