A lot of backtracking in the beginning, and a lot of repetition throughout. I listened to the audiobook as the local library had no text copy. This was fine, though it did make the necessary skimming (to skip the backtracking and repetition) a bit of a different chore, and perhaps leading to some gaps in my knowledge of the events of the book. I would skip the 3 or 4 minute tracks, finding that I could quickly figure out whether or not to skip again. I don't think I missed as much as I would if the tracks were longer. Also, this audiobook has me thinking of more audiobooks, to listen to during work!
The character Alicia is an interesting one, always has been. So I'm glad this one's focused on her. She usually has a stern self-reliance and a strong character with experiences that have given her the kind of confidence she needs to ensure her space is well-defended. Unfortunately, she weakens around Robert and other men, like her father, who engages in 'independence training' by ordering her to do things. It's no wonder she's so easily manipulated by various men, but easily lies to and firmly questions FBI women. Same goes for all the women characters in this trilogy, it seems.
At one time, Alicia and Robert discover their fathers have been experimenting invisibility on certain test-animals. Alicia's father goes through this self-righteous speech about the necessity of testing and how terrorism and shit, and when he finds out the FBI is watching them, he goes on another self-righteous rant about the necessity of mass-murdering these test animals for security and liberty and hoo-rah he's an american. Robert, in a rare moment of insensitive stupidity, agrees with this murderous irrational nonsense, and apparently even joins in. Alicia is subsequently traumatized. For freedom.
At one point there is a scene in which they order dinner delivered to them. Alicia uses the 's' word with regard to hunger, a use I find extremely, perpetually insulting and unnecessary. Unlike Things #2, there isn't nearly as much fixation on meals, bodies, and so on. This is exchanged for Alicia's intense obsession with Robert.
While this may partly be due to her isolation from social life, and the constant interruptions against her ability to communicate her liking to Robert, it's not presented as if these are the reasons. So, it's more of an annoyance and skippable material than any growing understanding of her character and her relational needs.
The ending was fairly unsatisfying except for the resolved sense of self Alicia gains, and overall I think Things #2 and 3 are unnecessary. I don't think it's possible sequels like these, with the structure fixated on continuing old stories, can possibly completely satisfy readers. Especially me. There is far more possibility in the theme of invisibility, and the author instead settles on thematic redundancy, repetition, and boring stories which don't really branch to anywhere.