Oh man, this one dragged on and on. Even before the story expands into galactic timescales, it's slow. And then it sprawls across billions of years, piling catastrophe upon catastrophe. Civilizations rise and fall in paragraphs. Time skips rob moments of their weight.
The grand ideas are still there. Dimensional weapons, pocket universes, the death of physics itself. Liu Cixin keeps swinging.
Maybe I just wanted this to desperately convert into the space opera finale. Instead, the story just kept going, and going, and going. The protagonist floats through events more than she shapes them. By the final pages, I wasn't very happy; just relieved it was finally over. I will definitely read The Three-Body Problem again, maybe Dark Forrest. But that's it.