The story is based on a manhwa but in the drama they followed an almost different storyline but not different at the same time. In the manhwa there were no filming scene, no telling Siwon's life through a movie, no Dawoon telling his parents to select the movie and Dawoon's mother was a sweetheart. In the manhwa Siwon was bit more of an a$$hole and Dawoon was a puppy running after him. In the drama Yoonjung never confessed to Siwon.
The rumour on the internet and Siwon's childhood photo getting leaked was more intense in the manhwa. They handled the situation more savagely. In short the manhwa was more of a them being savage and the drama covers the same thing but a sweet way. That is why they get all the positive feedback from me. The drama and the manhwa both are 10 on 10 in their own way. The awkwardness you can see in Siwon sometimes is because he is awkward in general. They talk about his in the manhwa. It wasn't them being awkward while acting. When Dawoon dreamed about Siwon after their fight, you can clearly see Siwon being different, as in clingier. The actors did a great job here as well. 10 on 10 again. Also they didn't introduce two important characters which I assume leaves a door for second season. Or should I say one? The guy singing at the beach is one of them. Siwon and Dawoon's friend Bawoo (the guy with glasses who saved Yoonjung form the stalker) was an out gay in the manhwa and the singer is his love interest. The other one is Dawoon's cousin. They had a lot of history. I'm highly anticipating a second season. They need to cover Dawoon's struggle too. Overall hats off to the whole team.