On June 30, 2011, the lead single, "A Bitter Day", was released digitally.[2] It featured the guest singer G.NA in the chorus and rapping by Yong Jun-hyung of Beast.[3] It was co-written by Yong and Choi Kyu-sung. The song peaked at number 10 on the Gaon Weekly Digital Chart[4] and at number 165 on the Gaon Year-End Digital Chart for 2011.
On July 5, 2011, the EP's title track, "Bubble Pop!",[5] and its music video were released. The music video has a cameo by MBLAQ's Lee Joon.[6] It was filmed in Okinawa, Japan.[7] Hyuna promoted the song on music shows from July 8, 2011, on KBS's Music Bank, MBC's Show! Music Core, SBS's Inkigayo and Mnet's M! Countdown.[8] The song reached number 4 on the Gaon Weekly Digital Chart[9] and finished at number 21 on Gaon's 2011 year-end chart. It has sold 2,694,310 digital copies.[citation needed]
On December 9, 2011, the title track "Bubble Pop!" ranked at #9 on the American music magazine Spin's "20 Best Songs of 2011" list.[10]
The song appears in the 2017 dance video game Just Dance 2018 as a song on the tracklist.
Promotion and controversy
Hyuna promoted the title track "Bubble Pop!" on music shows in July 2011. The EP's introduction song "Attention" was also used in the performances.[11]
In August, Cube Entertainment halted promotions because the title track's video, choreography and on-stage costumes were deemed by the Korea Communications Commission (KCC) to be "too sexually suggestive".[12] Cube Entertainment decided to promote the follow-up single, "Just Follow", featuring the rapper Dok2. Hyuna's performance on the Inkigayo music show featured the rapper Zico from the boy band Block B instead, and with lyrics that he re-wrote.[13]
