This drama made me a fan of Kim Tae-Ri. Nam Joo-Hyuk's best drama after Start-Up, both are true Blue Dragon Awardees, their visuals and acting get audience (me) emotionally involved. The drama also got very talented and promising 2nd leads Bona, CHW and LJM. Supporting actors were also impressive.
2521 has a great story, credit also the film makers.
The story is not predictable. As of this writing, it's episode 10 half way and still wondering what happens to Yi-Jin and Hee-do even if the present Hee-do is shown alongside. The cast performing one of the OST songs WITH was also a great move for the film makers/producers. Kudos!