It also features two CD-only bonus tracks ("Heart" and "Twenty Three") from KBS's television series The Producers, in which IU starred as Cindy.

[2] According to Scott Interrante of PopMatters, Chat-Shire uses lush orchestrations and complex arrangements that recreates a 90's chamber pop sound similar to The Cardigans.

[5] The track eventually achieved a Perfect All-Kill, as the single hit Number 1 on all of the major South Korean music sites simultaneously.

[10] Seoul Beats also highlighted the "personal quality" showcased in many of the album's tracks and praised IU's "growing maturity as an artist" and her willingness to experiment musically.

[11][12] Following its release, the album was controversial for allegedly using Britney Spears' voice and sampling her 2007 song "Gimme More" without permission in the bonus track "23".