I purchased this book because I enjoyed the video game based on it. Although this book has not as much action as the game, it has a strong atmosphere and I really like reading it.
There are a lot of passages which went missing in the game and the world seems much richer.
So if I had readed the book before playing the game, I would have enjoyed it a lot less. This book is a definit keeper.
On a downside it has a lot of deus ex machina moments, like Artyrom is in trouble and then someone apears and rescues him. Over and over again.