NOTE: I don’t follow Joy from Red Velvet and I didn’t read the manga, this review is solely based on the show itself.

LIKES:
Story development of FL, ML and the two groups/bands, and the CEO guy
Better character development and content for backstory, than the Japanese version.
The friends that stick together rather than go after individual glory/money concept was really well done. The cut throat music industry was well done in how it can divide artists/friends, how it is after money and doesn’t always listen to it’s artists. The singing bits weren’t dubbed, but the actors themselves singing and playing their instruments.

DISLIKES:
Directing wasn’t the greatest, because in some circumstances throughout each episode the characters waited to react, way too long. For example: Episode 6 at end/start of 7 Director had FL wait way too long.
Shaky camera, especially close up shots [it was as if the video stabilizer was removed].
The romance was slow paced and could be boring at times
Repeating music got old, but the first time I heard the song(s) it was catchy and decent in the pop genere.
No chemistry between FL & ML, more of a friends vibe, but their acting was fine.
Predictable Music-drama Fluff with typical teen drama tropes.
The plot kept switching between romance of FL & ML, among some side stories, to the story of Crude Play (their beginning, trials and future).
The writing made the FL dumb and the ML oblivious to everything around him (until maybe the last few episodes).
The love triangle fell flat and completely failed, maybe due to the childish aspect they created for the FL.

OVERALL:
Light content, easy watch, for a K-drama it’s plot was limited, but enjoyable. Kpop fans will love the OST. Better than the Japanese version, that cut content that was needed. [When I watched the Japanese version I remembered watching the Korean one, so had to re-watch to give an accurate review.] I won’t rewatch it again.