When I started this drama, I was hooked instantly. The first 10 episodes were an absolute blast to watch. I thought I finally found another 9/10 rating worth gem. But....sadly as the episodes went by the quality degraded considerably. While the first half was super fun, the second half became a nightmare to watch. Romance became scarce and main leads chemistry suffered a bit too. Totally lovable characters became horribly flawed. Plot became uninteresting. New sub plots kept on appearing which were out of place altogether. So I will rate this drama accordingly by rating the episode groups themselves.

First 10 episodes (1 - 10): Engaging story, good romance, great chemistry, lovable characters especially FL, sensible decision making, really good character development. Overall easily 9/10

Next 10 episodes (11 - 20): Still interesting story, okay romance, good chemistry, questionable character ethics, questionable character decisions, abysmal character development or maybe a little bit character regression itself. Overall 7/10

Final 10 episodes (21 - 20): Absolute mess of a story, scarce romance, lacking chemistry, boring and badly written characters, idiotic and flawed decision making, total character regression save for the ending. Overall 3/10

And thus the final rating, since we can't just rate this based on the good parts alone, is 9 + 7 + 3 /3 = 6.33 or better rounded off at 6.5/10. To summarize, I would say this was a really good story with major promise but got destroyed by very very bad writing, pacing and direction.

P.S. Would like to commend the OST though, absolutely wonderful.