When The Party's Over (song) - Wikipedia

"When the Party's Over" is a bare-bones piano ballad[7][8] that acts as a departure from the electro and R&B beats of her earlier output.[9] Music publications have noted its hymnal-like qualities and use of bass, as well as its minimal instrumentation, which spotlight Eilish's vocal abilities.[7][10][8] Rolling Stone editor Ryan Reed highlighted the track's "atmospheric vocal harmonies,"[11] use of vocoder and Eilish's use of her high vocal register, while Nicole Engelman of Billboard wrote of the "angelic hums" that accompany the singer, whose voice "[swells] up from a whisper."[12] Chris DeVille of Stereogum compared the song to the work of Imogen Heap and Lana Del Rey.[10] Musicnotes published this song in a 34 time signature with a tempo of 124 beats per minute in the key of C♯ minor, with Eilish's vocal range between the notes of E3 and E5.[13]

Eilish has described the song as "kind of a sequel" to her single "Party Favor" (2018), documenting when "you're on the phone with someone and you can't hear them, they can't hear you, it's loud, they're mad at you for some reason" and consequently thinking: "You know what? Fucking leave me alone."[14] It discusses the end of a relationship, a common subject matter in the Eilish's previous work, with the singer wishing to be "more than a party of one;"[12][15] Suzy Exposito of Rolling Stone described it as one of the more sincere songs off her debut album When We All Fall Asleep, Where Do We Go? (2019),[15] while Reed wrote that "each verse [grows] more mournful" as the song progresses[11] It opens with a sample of Eilish's debut single "Ocean Eyes" (2016), which Sean Ward of The Line of Best Fit argued demonstrated an "understanding of her own artistry."[16] No instruments accompany the vocals until the first chorus a minute into the track, where sub-bass is introduced.[4]