Lots of great puzzles and very few annoyances. If this had a stronger story, it would have been perfect.
I don't mean this as a negative. Professor Layton and the Diabolical Box promises puzzles and does nothing but deliver them. These are a diverse array of brain teasers of every imaginable varieties. There's pattern matching, lateral thinking puzzles, math problems and things that seem like math problems that aren't. Some of these are straight forward, some of them are tricks and you never know what's what. Some problems require a while to figure out. Some problems you will spend a long time trying to solve only to find a simple answer is revealed by a more careful reading of the clues. Puzzle-wise, I just don't think this could get better for this style of game.
The story leaves something to be desired. This has relatively story-related content--a couple hours at the very, very most--but what's there is sort of stitched together and random. Sure, there is an overarching plot that makes basic sense but the end reveal is just plain silly and unsatisfying. I don't want to spoil it but, seriously, it felt like a cop-out to me, like they started to build a slightly complex web of intrigue and just couldn't be bothered to resolve. Don't get me wrong, this is not a game that is driven by its story but what's there could have been done way better.
This all being said, Professor Layton and the Diabolical Box is still a nicely presented game w/ a charming artsyle and good music as well. Most of the puzzles are ultimately skippable and there's ample hints available so someone who gets deterred easily can still plug their way through the whole game but for those who want a challenge it's there. All and all, Professor Layton and the Diabolical Box does the primary thing it is trying to do exceedingly well and anyone who likes solving puzzles is going to have their hands full w/ this one.