Wow, I don't even know where to start with how awful this book is.
Terrible bi rep? Check.
Terrible girl rep? Check
Terrible fat girl rep? Check.
I loved Simon Vs The Homo-Sapiens Agenda and fell in love with all the characters (well, not Martin) and I felt especially drawn to Leah. So when I found out there was going to be another book, centered on Leah, I got excited. Then the blurb mentioned that she's suddenly bisexual, and I got concerned because there was zero indication or hint of that in the first book. But it couldn't be that bad, right?
Other reviewers have said it better: this story felt like fanfic. And not even good fanfic. It felt like the really bad fanfic that you don't admit to reading. The AU kind where everyone's gay and acts so out of character as to be unrecognizable in order to force together the writer's OTP that makes zero sense in canon but dammit they're going to make it work no matter what.
On top of that, there's no plot. It's just a string of scenes that are connected only be the fact they happen chronologically (aside from a couple of flashbacks). Leah exists just to be awful and condescending and rude to everyone, yet for some reason everyone still loves her.
There's also no heart. We never learn why Leah acts the way she does because there's zero reflection on her actions or feelings, and so she never learns or develops. She's the exact same awful person at the end of the book as she is at the start of it, and she's taken everyone else down with her. This is just Leah referring to herself as a bitch for 300 pages because isn't it hilarious when girls call themselves slur words? There's no reason to care about Leah, so there's no reason to care about anything that's going on around her.
There's a really awkward attempt at addressing racism that feels more like it was written as an overhanded after-school special message than an actual examination of racism and all of its nuances. It's there solely to give Leah one shining moment of being not completely sucky.
In a word, this book is superficial.
The first half dragged because nothing happened aside from Leah being rude, not knowing how to express herself, and constantly having brain freeze, stopped heart and flipping stomach, because that's what hormones do to seventeen-year old girls. And apparently being bisexual means you develop crushes on everyone. I couldn't take the plodding pace of non-action, so I did skim most of the second half starting around 60%. Thankfully, not much happened in that section beyond prom, Leah and her girlfriend being selfish and awful to everyone at prom, and the writer leaving a bunch of dangling threads.
This was a huge disappointment and read like the Ms. Albertalli just phoned it in.