"OMG" contains lyrics in both Korean and English that were written by group member
Hanni, Gigi, and Ylva Dimberg. Dimberg also composed the track with
David Dawood and producer Park Jin-su. Hanni said that she was inspired by "high school teen dramas where the girls are at their lockers and they're talking about a guy they like" when writing the lyrics. She tried to make the lyrics conversational and find the right words in both Korean and English so that "the pronunciation [...] sticks to the melody". The romance appears to be one-sided at times and drives the narrator crazy ("Wherever, whenever/ There ain't nothing else that I would hold on to/ I hear his voice through all the noise/ Don't let go of my hand for one second no, no/ Got no worries 'cause I got someone/ It's okay to be alone 'cause I love someone"). In the
refrain, Hanni sings, "I was really hoping/ That he will come through", hinting at the disappointment and melancholy that the narrator experiences. "OMG" opens with plucked,
staccato synth
chords and progresses with skittering
cowbells and anchoring
percussion in the pre-chorus. The chorus features vocal
chopping and the track concludes with layered percussion,
vocal harmonies, and piano. showcased through its hip-hop percussion,
Pitchforks Joshua Minsoo Kim described "OMG" as a "soft, minimalist R&B" track,
Hankook Ilbo popular music journalist Ko Kyung-seok deemed it a "simple hip-hop R&B" track. whereas Maura Johnston of
Rolling Stone deemed it a throwback to 1990s R&B with a "21st-century appeal" brought by the synths. The remix was described in a press release as a hip hop track with an
Afro rhythm. == Reception ==