I rated An Absolutely Remarkable Thing five stars when I first read it a couple years ago, which now turns out to be a problem. Not because AART isn't worth all the stars, but because ABFE is worth at least twice as many stars and Goodreads doesn't let me do that. I'm not super coherent right now because I just finished and all the thoughts are swirling around, BUT.

1) I loved how much more properly sci-fi-y ABFE is. Hank said in the FAART Discord Q&A that he wanted AART to be more accessible to people who hadn't read much (or any) sci-fi before, which makes sense and I think it was the right decision, but BOY was my nerd self mentally fist-pumping as the book got more and more into proper sci-fi territory. (That said, I do still think it's accessible/enjoyable if you liked the first book but don't usually read sci-fi.)

2) The ideas in this book are very Hank, and I feel like I could almost tell Hank wrote it even if I didn't know, but it never felt like the ideas were driving the story. 

3) I'm not sure I can say much more about...anything without getting into spoilery territory, though I may come back and add more later after my thoughts have cohered a bit and I can talk about things without directly spoiling plot. (Or I may not, which is probably the more likely possibility.) But for now, know that there are SO many extremely spoilery things I loved a lot and just go read the book okay? Okay.