While I enjoyed this book a great deal, there were a few elements that fell short of the heights achieved in The Three Body Problem.
Mostly, I found the protagonist, Luo Ji, to be passive and not nearly as rich in character as, well, any other major (and even minor) characters in the series so far. There is probably a meaningful reason for this, but for me, I just could not believe that Luo Ji was capable of making the difficult decisions that were necessary to reach the "Dark Forest" solution that ultimately saves Earth.
The literal "perfect wife stepping out of your dreams" subplot was also...I'm not going to say it was pointless, but it was pretty cliche in a series that has felt mostly free of this kind of plot. I understand the purpose of giving a character a brief taste of paradise to serve as motivation for enduing the absolute worst conditions in hopes of achieving that peace again...but when every other character has more complicated reasons for making the choices that they do this simplicity feels deeply unsatisfying.
I also felt like the revival of the Three-Body Problem game served little purpose, but given that this is a trilogy I imagine this will be more important later on.
Otherwise, this delivered more of what I wanted after finishing Three-Body Problem, and I continue to be blown away by how well Liu Cixin weaves together macrosocial theory, hard science fiction, and classic literature in a way that is approachable and emotionally resonant.