The lead single "Love Like Oxygen" is a remake of a song by Danish X Factor winner Martin Hoberg Hedegaard, originally titled "Show the World".

It features a disco-based funky rhythm that is reminiscent of Michael Jackson and a drum pattern that commonly appears in American R&B music.

The lyrics were written by Young-hu Kim, the lyricist of "Replay"—they compare changes in love to ice, water, and oxygen in order to express the pain of letting go of someone.

In addition to meaning "friend" in Spanish, "Amigo" (아.미.고; a.mi.go) is a shortened version of the Korean phrase "You will suffer if you love the beautifulness" (아름다운 미녀를 좋아하면 고생한다; areumdaun minyeoreul joahamyeon gosaenghanda).

[9] The album was commercially successful in South Korea; it debuted at number three on the MIAK monthly music chart, selling 30,000 copies.