First I will say that I have not (yet) read the book, I do own it but I don’t exactly have a lot of free time these days. That said, a movie should stand on it’s own merits and that is how I will review it.
Overall I would say the movie is borderline worth the money to see.
There are three main issues I have with it.
First the main character comes off as kind of dull. I mean that in the sense he is kind of boring and that he is kind of stupid. For example he assumes that the people he meets conform to the age and gender of their avatar. This is after he gives an onscreen narration about one of the good things about the Oasis being that you can have any avatar you want. I can understand a convention developing that for conversational purposes you assume people fit the age/gender of their avatars but no one would assume that its real.
He “falls in love” after less then an hour of conversation with a avatar of a young women who does nothing more then pay attention to him. I mean I am not saying that is unrealistic, but it is not endearing.
He just was not a great protagonist.
Second, there were two protagonists that were, in theory, important but were never given the screen time. In the book I am sure they are given enough but in the movie the scenes with them are just wasted. They should have either been written out or expanded.
Third, and the big one for more, the world was just not developed enough. The movie is set in thirty or so years. Despite this we have roman style debt slavery (you become the slave of the person you owe money to until you work the money off). A game company has what looks like a swap team that operates so openly they wear company logo’s. We are told names of wars and stuff but we are never given context. It is implied that getting jobs is hard, but never stated.
Thirty years is enough time for a lot of stuff to change, but not enough for you to make such basic changes to everything without any explanation.
The game company that has a swat team has their CEO personalty try to kill someone. Me, I assumed this meant that they had so much power and influence that he was above the law. Even if a cop saw him do it, he would just pay them and they would look away. Yet he was dragged away by the cops.