Professor Layton and the Last Specter is the very last Layton game on the Nintendo DS. It's technically a prequel to the other three that have already come out, but practically speaking that doesn't really make much difference.
Just like the rest of the Layton games, Last Specter starts with Layton finding out about some mysterious happening that requires his attention (in this case, a mysterious specter that is destroying the town of Misthallery at night). His assistant Emmy (and soon after the story begins, Luke from previous games as well) join him in solving puzzles along the way as they get to the bottom of the overarching mystery.
I'm sorry, Layton, but this specter does not look at all like it should if your solution was accurate.
First and foremost, I want to say that the overarching plot is just as nonsensical as the rest of the series. Totally ridiculous. However, that's not really why I play these games, so though I made fun of it liberally, I still enjoyed the rest of the game (mostly).
Last Specter has 170 puzzles in total (155 in game and 15 in the bonus content), and that's the real reason to play the game. For the most part, the offerings in this installment were pretty well balanced. There were a few I got stuck on (mostly the slider type puzzles, as pictured below - definitely my least favorite puzzle type), but I felt like it did a good job at providing clever and logical puzzles. If you do get stuck, there are 300 hint coins hidden throughout the game that you can use to unlock up to 4 hints per puzzle. (Or there's the internet.) Sadly, I only found 290 of them, but I opted not to go back and search for the rest for the sake of my sanity.
I hate this type of puzzle.
The minigames were about like always - hit or miss. I liked the fish one a lot, the train one was okay, and the puppet one was stupid (but really easy). Completing these minigames unlocks even more puzzles in the bonus content section after you beat the game.
New to the series was the addition of an entirely separate game - London Life, a game reminiscent of Animal Crossing. You are a citizen of London and you can go around doing jobs to earn money, buying stuff to trick out your living quarters, and running errands for people. Though fairly simplistic, it's a fun addition. Unfortunately, there's only one save file allowed, so if your spouse wants to play too you have to share a game.
Not too graphically intense, but it has a certain charm to it.
All in all, Last Specter is a solid installment of the series. If you end up giving it a shot, ignore the ridiculous plot and have fun feeling smart every time you figure out a particularly tricky puzzle. And remember - every puzzle has an answer!