Here's the thing, this Movie was made specifically for the fans that read the webtoon, NOT the ones that ONLY watched the drama(that doesn't mean they can't watch though).
The original Webtoon started back in 2010 and ENDED last year in March/April 2017, so the people that watched this movie already knew all about the characters, and their story, but went to watch because the K-drama butchered a lot of them, to a degree that it p*ssed off even the author Soonki herself, and they all wanted them to be given justice accordingly to the original Webtoon that everyone loves.
Believe it or not the movie was made with direct supervision from Soonki, so anything you disagree on it is going against the author's vision, which, btw is not a bad thing at all, it only means you'll probably not(not 100%) enjoy the webtoon, meaning just stick with the Drama.
Just sharing some information because I'd like people to not discourage fans from watching, specially because it was a love letter from Soonki herself to her fans who gave her support for all these years.
The original Webtoon started back in 2010 and ENDED last year in March/April 2017, so the people that watched this movie already knew all about the characters, and their story, but went to watch because the K-drama butchered a lot of them, to a degree that it p*ssed off even the author Soonki herself, and they all wanted them to be given justice accordingly to the original Webtoon that everyone loves.
Believe it or not the movie was made with direct supervision from Soonki, so anything you disagree on it is going against the author's vision, which, btw is not a bad thing at all, it only means you'll probably not(not 100%) enjoy the webtoon, meaning just stick with the Drama.
Just sharing some information because I'd like people to not discourage fans from watching, specially because it was a love letter from Soonki herself to her fans who gave her support for all these years.