Well...if anything it sounds like this version of “IT” is much truer to the Book than the made for TV version with Tim Curry. “IT” (the book) is VERY dark and twisted. (Stephen King years later admitted he was high on drugs most of time he was writing it, and it many ways it reads like a bad drug trip.)
“It”, the book was very good, except for the ending. I don’t like to look into drains after that one and the movie “Phantasm”