Finished this game yesterday. The only other Layton game I've played was the first, and it had a charming, quirky story that kept my attention until the end. This one? Well, let me sum it up like this: The story in Professor Layton and the Miracle Mask sucks donkey balls!
The big plot twist is so blindingly obvious that it's impossible to not see who the villain is from the earliest parts of the plot, yet every single character in the game is not only oblivious to this, but in fact don't even get close to suggesting the possibility. It's very frustrating to see the characters standing around, speculating about the identity of the bad guy when you know exactly what's going on.
Then you get to the end, which actually manages to top The Dig in its ridiculous sugar-sweet happiness ("consequence" is clearly not a word in Layton's universe). At one point during the final few scenes I literally groaned out loud from how absolutely retarded the whole thing got. Then suddenly two characters I've never heard about before come in and turn out to be central to the whole thing. Say what?
I know this game is written so that it can be enjoyed by children, but there has to be a limit to how insipid, melodramatic, predictable and ultra-happy a plot can be before it crosses a line. The first game in the series did it right. This one trips over its own shoelaces before even hitting its stride.
The game is great (except for a few puzzles that are inadequately explained, not giving you all the information you need to solve them), but the story is a stinking pile of crap.
The stupidest moment, which is a major, MAJOR spoiler: