DISCLAIMER: I'm a music listener, not a music expert, so forgive my mistakes.
The instrumentals are so simple, yet so beautiful. They create the perfect ambience, adding instruments one by one and building up the song. It starts very slowly and gets powerful at the end.
It starts with slow piano chords setting up a sad mood. At 0:45 the chords get faster as if they are building up some hope. Then at 1:04 a hum starts at the background giving it a soothing sensation. At 1:35 the acoustic guitar indicates something is coming. Then at 1:49 we get the drums and a melodic guitar making the song very relaxing, with a very discrete bass making it even more relaxing. Finally, at 2:37, we get the full instrumentals with full drums and an electrical guitar, with the song getting more powerful until the end. Of course, to complement it all we also have IU's heavenly voice and the amazing backing vocals at 3:08.
