I'm really surprised by how well the trilogy ended. Going in I expected it to be about as good as the 2nd instalment (which I gave 3* to) - not horrible, not great in any way.
But boy was I pleasantly surprised. This final part builds very well on the plots already established and even casts some of them in a different light, a literary move I always like.
Most of the book I thought "well I see how this is going to end; I'm not exactly happy about that ending, but it makes sense and would make this a good book." Then Lawrence pulled a few twists and voila, the book is suddenly very good indeed.
Glad I read the entire trilogy - this alone made it worth it for me.
Oh, and I also kept getting flashbacks to Steins;gate again, just as in the 1st one (but interestingly, not the 2nd). There was timetravel, talk of parallel universes and time loops, but in case of this book, I actually enjoyed it.