If you've read the book, you'll like the game!
As a big fan of the book, I bought the game immediately and I couldn't get of it. I loved the puzzles you needed to solve and the graphs we're pretty good, and for those of you who haven’t read the book, I can tell you this: the puzzles aren't hard at all; you just have to think logically and go from one place to another.
I recognized all the place since it's based on the book, but I had forgotten almost everything when it comes to how the solved different puzzles, so some things we're quite surprising, but as I said before the puzzles aren't hard at all, just think logically and don't get pissed off if you don't solve it right away.
Now for the game play (Which quite disappointed me), the camera angle sucks, the character covers almost 1/3 of the viewing space, and you can’t zoom in or out, the controls pissed me off in the begging. They weren’t those that I we're used to play with and I couldn't find a way to change them. Another thing that made me thing "Oh good..." was the combat, the combat is based on clicking with the mouse and hope that you get the right combination since you have to click in a certain order. (Some combats may get quite frustrating because there will be enemy rushing to you, but it isn't hard to defeat them because you can change the difficulty on the fights).
A thing that was quite poor but also a bit funny, was that sometimes you can stand right next to an enemy and he won't see you, but sometime this won't work.
Now for the puzzles, I like the puzzles very very very very very very very very much. Not too easy and not too hard, just perfect. Since I almost had forgotten everything they did it wasn't hard to solve the puzzles some of them are ridiculously easy when and some takes some minuets to figure out. The only annoying thing about some puzzles is that you need to find things to complete them, like statues etc., it can get boring to search for them.
The game overall is great, puzzles that keep you up for hours and it's really worth the money for those of you who read the book!