To be clear, this is not the Zelda II of the Professor Layton franchise. It features the same combination of woodgrained old-world feel and Osamu Tezuka-style character designs, a similarly puzzle-minded citizenry, and a storyline intriguing enough that, somehow, the player manages to be drawn into a world that ostensibly exists only as a puzzle delivery system. There was absolutely no reason to change the formula after the magical Curious Village, and developer Level-5 knew it.
The Layton series is proof that almost any activity can be grafted into a video game to make an engaging experience. These games do for brain teasers what RPGs have done for menus.
This time, the professor and his apprentice Luke visit one of Layton's teachers, only to find him dead on the floor, seemingly the result of a cursed artifact, the Elysian Box. In his apartment, the pair find a ticket for the Molentary Express, a luxury train, and head off to find clues to both the death and the secret of the box. Everyone they meet along the way has a puzzle that needs solving, puzzles appear on doors, walls, and as obstacles blocking Layton's path; in fact, just about every in-game element that isn't a puzzle reminds Layton or Luke of a puzzle.
The puzzles range from math challenges to riddles to mazes -- the same kind of assortment found in the predecessor, though mercifully free of puzzles about pouring liquid into three different containers to measure it. New challenges replace the last game's "Strange Gizmos" and other distractions. These "sidequests" involve collecting ingredients for herb teas, keys for a diary, camera parts, and, most memorably, items to entice a fat hamster into working out. The tea minigame in particular seemed to interact much more with the main game than the last game's extras, and thus offered more motivation to explore it.
Though I'm loath to admit that the story holding all these puzzles together held my attention, I know I must not be alone, since Level-5 is releasing a Layton movie. I found the storyline in Diabolical Box to be more adventure-filled, more intriguing, and dramatic than the original game -- right up until the kind of stupid ending. Oh, well. Every moment before that was satisfying. This story is presented using what seemed to me to be significantly more voice acting and animated sequences than before.
If you played and enjoyed the first game, then there's no mystery at all about whether you'd enjoy Diabolical Box. If you have yet to play Curious Village, there are a few elements in the sequel that spoil some major secrets, so I recommend giving it a try first. You'll be part of the vocal community begging Nintendo for the next one soon enough.