Honestly I was a bit disappointed too. Maybe it's just because I'm sad that the story ended, but I also think that the ending was kinda rushed. And also I know the manhwa itself has nothing to do with romance and I believe it's decently done for a story of this type, but I didn't really like the ending Sung Jin-Woo and Cha Hae-In got. I'm sure everything went well afterwards but I still feel like something was missing.

as someone how read the light novel i recommend to read it after where the main story ends because it show what happening after everything dont wanna spoil anything but it tellls the story until Jin-woo gets old
or maybe just hope that they do manhwa for does extra light novel pages I think it can give about 6-10 chapters