The Betrayals is a fantastic book. I know there have been mixed reviews, and to an extent I understand them. Your ability to enjoy this book will be defined by your willingness to embrace abstraction, and so it won't be what all readers are looking for.

Collins does not shirk from her narrators' unlikeable qualities, which can sometimes make for uncomfortable reading. The plot of this story has definite weak moments, where either too much or too little is given away, and the central concept of the grand jeu remains an abstract mystery throughout, which may frustrate readers. Personally, the subplot of the Rat is a particular point of contention, as I feel that this thread added very little to the story. I also have a personal preference for more certain, definitive endings - but I won't go into too much detail, as I'd like to keep this review light on spoilers! These, however, are the main reasons I have not rated this book any higher.

Despite these criticisms, I genuinely think that this book is a fantastic achievement. What it does well, it does excellently. 

The glory of The Betrayals is not in its plot, but in the way it captures themes, concepts, atmospheres, and emotions. The snatches of the grand jeu which we are allowed to understand contain sing with love for classical music, philosophy, mythology, modern art, and even mathematical principles. Collins herself notes taking substantial inspiration from The Glass Bead Game by Herman Hesse. I think the story also owes much to George Orwell's 1984, as the dystopian society framing Montverre is much like an infant version of Oceania.

The grand jeu is an ode to interdisciplinary work and divergent thinking. The plot of The Betrayals pushes its central characters further, to consider the moral obligations of scholars towards their art, pupils, and wider society. This book is a maze of intertextuality and social philosophy, and I think, in some ways, it might struggle to find its audience. But it's certainly found itself a loving home on my bookshelves.

I know they say it's about the journey, not the destination, and boy was this a journey. I'm not too sure about the destination.
I guess this is my way of saying I'm still not too sure how I feel about the latter part of the book, although I absolutely loved everything until then, and I am somewhat satisfied with the ending. It's not necessarily a bad feeling