Director You Sang-hun's gimmicky omnibus Acoustic is composed of three shorts about musicians, that also happen to star musicians (as well as Shin Se-kyung, an actress whose earliest claims to fame are being featured on an album cover and weeping memorably in the music video for Seo Taiji's "Take Five" when she was just eight-years-old). You could call Shin a musician mascot. This is what is called riding a concept hard.
There are other motifs that ostensibly tie the shorts together. Like the fact that in all three shorts, the characters eat Ramen with significance. In the first mini-movie ("Broccoli"), instant noodles are consumed ostensibly to stave off a fatal diagnosis. (Credit the sodium.) In the second entry ("Bakery Attack"), the two leads eat Ramen because they're "starving artists" (played by real-life CNBLue megastars Kang Min-hyuk and Lee Jong-hyun) who are waiting to score their first big hit. (Which they do! No more Ramen ahead!) In the third ("Unlock"), I have to assume the inclusion of instant noodles is to show that in the not-too-distant future, it's one of the few things you can count on still, especially if you're a girl (Baek Jin-hee) with a broken iPhone and a robot arm on the fritz. (Ramen, now and forever.) As connective tissue goes, the presence of microwavable Ramen is not the greatest idea but this is what we have to work with here, people.
A third motif almost emerges. In "Broccoli" and "Unlock," the plot features a song constantly sampled and featuring an extended lyric around -- um -- broccoli. (Why not Ramen?) "Bakery Attack" and "Unlock" both are headlined by K-Pop sensations (the latter being Lim Seu-long of 2AM). Why they didn't get a song about broccoli for "Bakery Attack" or a cute teen idol for "Broccoli" is unknown. I'm going to hazard a guess that they did have a singer (who dropped out) and they did have song chosen (that CNBlue refused to sing). I'd like to think some artistic integrity was at work here even if it had to do with what's not seen.