I watched the film, as sometimes find such short episodes interruot the story's flow.
Kang In Soo and Lee Sang are really sweet together. Their characters are quite understated; there's no OTT melodrama or unnatural discomfort. Sang-yi's slightly shy and humble, yet supportive and positive personality sits so well against In-soo's deeper more confident one. They compliment each other well.
The 2 more intimate scenes were nicely done and the actors were believable. No wooden or uncomfortable posturing.
I liked the story, but did feel that some of the scenes in which feelings were being individually contemplated, against the fitting soundtrack, were a little lengthy. They could have been shortened and a bit more added to other parts of the story; possibly their relationship deepening, or a bigger hint of their musical success to come.
A very nice watch though.