Eyes of Dawn is really good. It's a very tough watch, though. And since it's from 1991, the production value was noticeably lower than we're used to seeing in Korean dramas.
(I've only watched three episodes so far and had to put it on hold because in three episodes, it had already depicted rape, violence, and human experimentation. I don't think it's exploitative, though, and nothing overtly graphic, but still very hard to watch.)
