Not a bad nor good game. The problem here is that it's a Layton's game.
The episodic format makes the misteries easy to guess, and the history of each is too short and simple because the duration of the cases. After finishing the game, Level-5 don't answer the most important questions: who is sherl and why is a talking dog? and where is Professor Layton? (literally is called Layton's Mystery Journey and it's never discussed in the game).
The big problem here are the puzzles, from someone who has played the six Professor Layton games (and the crossover), they are very easy, too easy to resolve. The absence of akira tago is noticeable, besides the dificulty, some others have the "thinking out of the box" with stupid and nonsense answers.
It looks like it's oriented to the casual public that has never played a professor's game, but that leads to what was said above: simple history and easy puzzles, making those who have played the entire saga find it simple and boring. Hopefully Level-5 learned and don't do this in The New World of Steam 🙏

I never managed to finish this, mostly because the Switch came out while I was playing it, but also because it's just not as engaging as the other Layton games. In the end, I'll give it 2 stars because it's playable, not problematic, the cutscenes are nice, and a kid might even like it. To be honest I'm pretty sure that's the target audience.

But the 3D graphics don't suit the Layton style, the characters just aren't as interesting, and the puzzles are way too easy. Also, while I don't mind focusing on cute little detective stories over the main plot, the main plot that is there really isn't interesting enough to keep you playing. Not only that but the only good plotline didn't even get resolved here because they were trying for another trilogy.

The anime based on it is better than it in many ways though, strangely enough, maybe because it's in 2D or because they actually resolved the only interesting plotline.

I'm very conflicted about this game. On the one hand Katrielle and Ernest are adorable characters and I love them both a lot. On the other hand, the story is fairly weak and the puzzles are not as hard as in the other games. Feels very disconnected from the rest of the series, which Layton Brothers did as well. But in that game the gameplay and tone were So different that it feeling disconnected was warranted. They tried to do the same thing here, but with such a similar game style to the original six games the disconnect feels off and weird