Zimzalabim

Primarily an EDM-influenced electropop track that resembles a "colorful parade" and showcases an extravagant soundscape, the song was composed by production duo Caesar & Loui, Ollipop and Hayley Aitken with Korean lyrics written by lyricist Lee Seu-ran, which tells the listeners to "unfold a dream" that is "held deeply" in their heart.

[3] The group released a trailer video on June 10 which announced the full-scale start of The ReVe Festival through their YouTube and V Live channels.

[5] Musically, Tamar Herman of Billboard characterized "Zimzalabim" as an electropop song with "funky percussive melodies, tinny hip-hop chants, EDM dance breaks, and chill, groovy moments".

[10] On June 10, 2019, the trailer video titled "Special Competition: RVF D-10", was uploaded through the Red Velvet's official YouTube channel.

The music video is set in a fantastical amusement park, where they ride roller coasters through the skies, throw a tea party in a spinning teacup and perform the song alongside sentient instruments.

[12] Emlyn Travis of Buzzfeed noted the video as "magical" referring to its "carnival rides, floating instruments, tea cups, and a hefty dose of fantasy".

[14] On June 25, 2019, a flash mob performance video, titled "ZIP.CODE : SEOUL" was uploaded to the SM Town official YouTube channel.

Tamar Herman of Billboard magazine viewed the track as an "extravagant soundscape", adding it as a "genre-hopping song, which incorporates an addicting chorus".

[22] It became the group's fourteenth consecutive top-ten single on the World Digital Song Sales chart, reaching number 10 three weeks after its release.