Ryan Ruppe’s review published on Letterboxd:
Ready Player One is bad and dumb but kinda fun in spite of itself. It plays out with basically no character development and almost zero sense of peril. The characters have plot armor the whole time and you know how it's going to end during the opening monologue (yeah, there's lots of narration).
It felt more like a YA Emoji Movie than anything else. I think this is because it's a movie that is supposed to be a love letter to video games and 80s pop culture, directed by a guy who has no love for those things. The only time it seems like Spielberg is having any fun is during the Overlook Hotel/The Shining scene, and even that doesn't move beyond licensed reference into anything substantial. Speaking of licensed references, they're there, everywhere. All of the time. Like, way more than The Lego Batman Movie, which at least treated the references with a laugh instead of the deadly serious value that's placed on dumb pop culture in this movie. It's a movie that divorces pop culture references from any kind of substance or value. Cool things are cool just because they're part of some arbitrary canon.
The plot is straightforward to the point of obviousness, and the characters are, at most, one note. It hits all the clichés: underdog/David & Goliath, plucky kid vs. the angry CEO and his corporation, chosen guy helped out by the more skilled girl.
As for book accuracy, I haven't read it. My friend who enjoyed the book but was aware of its flaws thought it was much worse than the book. He called it “the Big Bang Theory version of the story”.
The people who sat next to me enjoyed it, they excitedly mentioned every time they saw a thing they liked referenced on screen. It's big dumb fun, with a focus on dumb. But hey, I would let my kids watch it at home if we cut out the one f-word added to guarantee the rating was bumped to PG-13.