First of all, i have to question his choice of title. It may be thematically appropriate, but it makes it bloody hard to search for online. It also makes it slightly difficult to talk to other people about. Someone asked me what book i was listening to currently, and i said "You", and they gave me a very puzzled look until i quickly explained. ("But I asked _you_ first!" "Third base!")
"You" is the story of an ex-nerd college dropout, Russell, who decides to go back to to his still-nerd friends from high school, who founded the famous video game company "Black Arts," and ask them for a job. Needless to say, things are not going great at the company at the point he joins it, and more problems are around the corner. Because "guy gets a job, reconnects with his old friends, and lives happily ever after with no difficulties whatsoever" would not be an interesting story.
Back when he was still a nerd in high school, Russell helped his friends develop what would become an underground hit game, which then developed into a series, and then got a publishing deal. In the process the series and its tie-ins manage to morph through pretty much every game genre existent up through the 1998 the book is set in. So the novel serves as a recapitulation of the computer game industry from the early 80s through most of the 90s. If you're interested there's an article by Austin Grossman about what actual games influenced the imaginary Black Arts games. (Though you should beware depending on your threshold for spoilers, since it obviously gives a rundown on a lot of the games in the book and a few details of some of them.)
The book is technically classified as "Mystery, Thriller and Suspense", and i have a hard time mustering a coherent argument as to why that is the wrong categorization. It seems like it _ought_ to be in Science Fiction/Fantasy, but there's no hard and fast reason for justifying that opinion.
So let me say that this is not a bad book. In fact i think it is a good book, possibly even a pretty good book, however it suffers form a couple handicaps that keep it from quite reaching what i imagined its full potential to be.
First, "Soon I Will Be Invincible" was a hard act to follow. I'm glad he came out with a decent second book since so many authors who knock it out of the park with their first effort seem to turn into one hit wonders. However "You" _does_ suffer in comparison.
Second, speaking of fantastic first books that make me nervous about the author's future, "Ready Player One" came out a couple years ago, and handled the 80's/90's retrospective very well. By focusing almost exclusively on video games, "You" manages to hit several points that "Ready Player One" missed. However by virtue of being second to market and that very same focus, it seems to lack quite the same "wow" factor. (If you have read neither book yet, i would suggest starting with "You" and graduating to "Ready Player One", unless you think you disagree with the rest of my analysis.)
Third, "You" is very clearly trying to be a "literary" book. There is a lot of focus on psychological elements and on character relationships (though a lot of that attention is focused on the relationships in those (retrospectively) halcyon days of high school, not what's going on in the here and now.) There's also a lot of metaphor. At a certain point the characters from the game start showing up and talking to Russell. I briefly wondered if there was going to be some actual magical explanation for this, then less briefly wondered if he was just going on the deep end, before finally deciding it was just another metaphorical tool for prompting/showing Russell's character development. Now being "literary" isn't necessarily bad (cf. Zelazny) but in this case i think too much emphasis was placed on the literary at the expense of the suspense and action, especially toward the end of the book. I definitely felt it ended with more of a whimper than a bang, with a plot thread or two i expected to be resolved ending up being mostly dropped instead.
And finally, the book gets 90-95% of the stuff about the game industry right. Which means that as an ex-video game programmer some of that remaining 5-10% really jumped out at me. And some of the bits that are factually wrong are actually metaphorically true. In particular, the plot depends on the core game engine, which has been in constant development for over a decade including multiple ports between systems, having a densely coded ancient, almost eldritch core, that no one can actually understand anymore. It is a black box into which API calls are cast forth and _mostly_ sensible answers come back.
I've dealt with a game engine of almost the same age, and that is definitely the mythology that we bandied about amongst ourselves. "Who knows what's going on in the depths of the old code?" However on the rare occasion where something actually went wrong, we dove into that code and debugged it and fixed it, and perhaps had a laugh or two at the almost ten year old comments that we found along the way.
And perhaps that's why i keep thinking it ought to be science fiction. I'm torn between going "that's just wrong" and believing it's some alternate reality where ancient code really could become as complex and alien as we liked to imagine, when we weren't busy actually debugging it that is.
But there are a lot of details about the gaming industry that are correct, or at least that _ought_ to be correct based on the mythology game developers believe about themselves, so if you're not quite as familiar with the game industry as me, or are slightly better at maintaining your suspension of disbelief, you might enjoy it more than i did.