- Contested Sequel: Fans of the Layton games are deeply divided as to whether this game should be considered a true sequel to Hershel Layton's saga or merely an interesting spin-off, with the most frequent points of debate being its looser, more open-ended plot, its mostly superficial ties to the games before it, and the proliferation of stock "trick question" puzzles at the expense of deeper, more challenging ones.
- Foe Yay Shipping: A bit between Katrielle and Emiliana, if only because Emiliana is unusually concerned with proving her superiority to Katrielle, yet she'll risk her career to save Katrielle from being arrested. It's one-sided, though.
- Most Wonderful Sound: The satisfying "ding" of discovering a hint coin is topped only by the discovery of ten hint coins at once.
- They Wasted a Perfectly Good Plot: The two big mysteries in the introduction are that of Hershel mysteriously leaving a young Katrielle and the origin of Sherl the dog. While the former doesn't get mentioned almost entirely after the first hour or so, the latter does get a passing mention in the form of a case coda.
- Trailers Always Lie: All the promotional material for the game suggests that there will be an overarching arc of Katrielle searching for her father, while his disappearance is really only mentioned in a few cutscenes and Kat is only seen searching for him in the intro.
YMMV / Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy