It's a kidlit mystery. I read it back when I was a kid, and liked it plenty then. I wanted to re-read it to see if/how it held up, especially after reading Chuck's review (in his case, reading it for the first time as a grown-up).
When I was a kid, I read it intensely trying to solve! the! mystery! (I failed; i.e., I didn't solve it sooner than the protagonist[s].) And then I re-read the book intensely looking for clues I'd overlooked the first time.
As a grown-up, I still remembered the answers to the big mysteries. (When I thought about how to use the [SPOILER REDACTED location on MIT campus] for Mystery Hunt, I thought about The Westing Game. If you know, you know.) Thus, re-reading, I let my attention wander to other points, notably character development. There wasn't a ton of character development, but it was kinda the point of the game within The Westing Game.
In the story, the 16 heirs of Sam Westing think they're showing up for a plain ol' will reading, but Westing turned his will into a sort of murder mystery game. The heirs are paired off into eight teams, and then flounder about for the next few months.
Westing did a strange thing. Most wills don't work like this. Why did he do it? Apparently, he hoped that partners would help each other with their flaws. Mostly. Except some characters don't seem so flawed, and don't change much. That's not terrible, but then you think: Sixteen characters is a lot for a kinda-short book. Why did the author include so many?
Then I thought about the pilot episode for that TV show The Goodwin Games. In the pilot episode, heirs at a will reading are surprised when it turns into a sort of puzzly game. Their father has carefull arranged this last-ditch effort to bring the estranged family together again. The show concentrated more on fixing family problems than solving! the! puzzles! (Especially after the first episode. Apparently, the network executives saw the pilot and said, "This is great! But ditch the puzzle-y bits which distinguish this show from typical network fare.") But I still think about that show, and what it was trying to do…
Anyhow, right, The Westing Game. Not a ton of character development, but there was some, and it was a motivation behind the game itself. Not the biggest part of the book, but I'm glad I didn't totally overlook it this time, unlike back when I was a kid.
Lately, I've been figuring out how to read books without giving money to Amazon. In my case, that means figuring out how to read books not-on-Kindle. I checked this physical book out of the public library. Yeah, it won't make much difference to Amazon; but I'm still glad I'm figuring this out.
