You're downvoted, but I agree. I found it basically a hodgepodge of 80s references over a basic story with one-dimensional characters (the heroes are Very Good and the bad guy is Very Bad). I would have assumed that it's aimed at young children, if the references weren't forty years before their time.
It's not just that, but also the main protagonist is written terribly and never given any real faults or challenges to overcome. During the entire book there is never a challenge that is not resolved by the next paragraph.
The Japanese friends that he makes are grossly stereotyped and are kept one dimensional during the entire book as well.
The main character also strikes me as incredibly creepy, and to a level where he could be classified as an para-social stalker. Just comes off as being a terrible person overall.
Spielberg's movie however is fantastic and one of those rare instances where the movie truly does outrank the book.
The film even has a proper ending which in itself is hugely thought provoking and something we definitely should consider. The book, if I remember correctly, just sets up for another book.
It was also a great book!