This title refers to a "game" the characters are playing: find the answer to Sam Westing's will, and win $200 million. But it also refers to another, similar game that only the narrator and one character know about, which we won't spoil in this section. Both of these games are kind of like chess, which is a subject that comes up a lot in the book: there are teams playing for strategy, with pawns, queens, and sacrifices. The Oxford English Dictionary (by the way, this might be the best dictionary to ever use in a lit. paper) tells us that the first, most popular meaning of "game" is "amusement, delight, fun, mirth, sport" (OED "game," n. 1.1). This isn't how most characters take it, though: some of them are uber-serious about playing, and are playing to win. One thing for us to think about, then, is whether this "game" is anything more than amusing or fun for us. Does it have a darker side?
The other cool part of the title is its subtitle: "A puzzle mystery." Have you ever seen another book with that in its title? We haven't either. So, what does this part of the title do? Well, it tells us what the genre of the book is – always a good thing – and it also tweaks that genre. This title says that the book isn't any old typical mystery. It's also a puzzle. While the book keeps secrets from the characters and the reader, readers always have more pieces to the puzzle than almost any one character does. Maybe we can solve it before the characters do!