I managed to watch it this past weekend, and overall it was pretty good, arguably the best "game to film" adaptations, but that's no doubt in part due to the archetypes of the source material.
It feels as if the movie at one point existed as an outline for a game's plot, except more action-heavy at the end. I wonder if that is literally the case. There's even a group of extras on screen for 4/5ths of the movie that in a game, you'd presumably get puzzles from while driving the main plot forward.
There is some AMAZING fan service in the movie though, and if nothing else,
the soundtrack has some incredible versions of classic Layton tunes.
Luke's voice was a little grating, but perhaps because he was jabbering over the entire opening credit sequence, which seems like something that may have been added to the dub to those unfamiliar with the games. Also the opening credits have some hefty spoilers for the games, if you are eagle-eyed enough to make the connection and care. There's also a certain awkwardness to the pacing that is forgivable in the games, but keeps the movie from being something really special with lots of crossover appeal.
The only thing missing is a scene after the credits where Layton throws his mentor's pocket watch (or whatever) off a cliff, then at the bottom a man with spikey hair in a blue suit catches it, crushes it, and quips "I see Professor Layton, that you have no objection..."