I haven't read the book, so I can do no comparisons in that regard.

Here's what I can say about this movie: the visual effects were quite good. Not realistic, but that was not the goal. On the contrary, their goal was establishing a virtual-world with an aesthetic comparable to modern games, such as Overwatch and the like.

However, this seems to be the only redeeming quality of the movie. The romance was forced, the story was uninteresting and not compelling, the characters were largely underdeveloped, the exposition was lazy, and the humor mostly fell flat. The writing was an afterthought, and the movie tried and failed to make up for this with its impressive graphic effects. Seeing the high reviews and Spielberg's name on this film gave me high hopes, but overall, this film was a disappointment and a waste of two hours.