"Cupid" was favorably reviewed by several music critics, ranking in the top 10 of the K-pop year-end lists of PopMatters and Idolator.

[4] Oh My Girl's debut showcase was held on April 20 at AX Korea in Gwangjin-gu, Seoul, where they performed songs from the album for the first time.

[13] "Hot Summer Nights" is composed by Alexander, Swedish songwriter and guitarist Andreas Öberg, and American musician Rinat Arinos (originally from Israel).

The song is about walking on the beach with the person you love; group member JinE said it "reminds you of a good summer memory".

Scott Interrante, writing for PopMatters, described the song as "the perfect distillation of everything K-pop should be: it is saccharine almost to the point of nauseating yet also unusual and unpredictable".

[12] At the end of the year, Interrante ranked "Cupid" ninth on his list of "The Best K-Pop of 2015", saying the song "captures the electric feeling of being young and in love".

[11] Jacques Peterson, writing for Idolator, described the song as "simultaneously hypnotic and jarring" and called it the "surprise rookie gem of the year".