I happened to have read the book before I started watching this series, week by week patiently (even though I'm more of a characteristically binge-watcher!) and first things first, i was engrossed in the world presented before my eyes. The cinematography is stunning, and I particularly loved the way they synchronized shots cutting through the different timelines of young unmarried Sunja and grandmother Sunja.
One of my biggest criticisms would be how they handled the relationship development of Sunja and Isak. Both the actors were extremely well suited for their roles, but Isak's character should have been handled in a more authentic way. He was glossed over (in my opinion) to make way for Koh Hansu. Koh Hansu's backstory (which was entirely made up by the shows creator and has nothing to do with the original book) which took up an entire episode, was very jarring, they should have launched it after all the episodes were out, maybe as a season's special or something of a similar fashion. It broke the flow of narration.
That being said, I am still looking forward for the next season.