I agree on the first half hour, but the last hour felt long to me.
Not that it's remotely in this same ball park as a film, but the 1984 film covered the entire book in 2:20. Just find a middle ground. 3:40 (1.5 times the 1984 length) for the book means two 1:50 or so movies. Heck even twice as long and this was 20 minutes shorter.
Part of that is my own general bias to be fair, 2 hours or so is when movies always start feeling long for me, even if I like them. At some point it becomes a task and not an escape.
If others enjoyed the length or thought it was about right, that's cool. And as I said, I liked it. Just wasn't blown away by it and the length played into that.
Again, JMO.