Musically, the album is diverse with genres spanning from pop, house, hip-hop, R&B, and pop-punk.[5]
The Core contains ten tracks, with the opening track "Xignal" being a spacey, synth heavy instrumental intro. "Gala" is a ballroom inspired house and rap track that features the members of XG rapping braggadocious lyrics about their style and high fashion. It was released as the first pre-release single to the album. The lyrics describe members turning the a "Met Gala into an 'X-Gala'". "Take My Breath" is an upbeat dance-pop track taking the electronic direction of "Gala" and softening it with a bubbly sound and lyrical contents of romantic love.[6][7][8] It features a French house leaning production with elements of funk.[9]
Staying true to the group's self-described roots, "Rock The Boat", "No Good", and "Up Now" are R&B and hip-hop songs.[8] "Rock The Boat" has lyrics revolving around sensuality and romance. It includes references to the R&B singer Aaliyah, who has a song with the same title.[8] "No Good" is a "silky" track featuring lyrics of confrontation. "Up Now" is a "laid-back" pop and R&B song with sounds reminiscent of the early 2000s similar to Doja Cat.[6][8]
The sixth track, "Hypnotize", served as the album's lead single. The song is a "runway-ready" techno house and dance track with production featuring rhythmic piano lines. Lyrically, the song talks about enchanting the listeners into a dreamy, hypnotic state.
"O.R.B. (Obviously Reads Bro)" is described as a "bratty" pop-punk song that echoes sounds of the 2000s.[5][8] The title references the term of endearment the members call each other and the bond it has represented since their training as idols.[8]
"4 Seasons" and “PS118” separate the group into fully vocal-led and fully rap-led songs. The ninth track, “4 Seasons”, is a laid back R&B song featuring an acoustic guitar. The song consists of vocals from Chisa, Hinata, and Juria. The final track, “PS118", is an "old-school" boom-bap rap song.[5] The song was originally the solo debut of Jurin, the group leader, featuring Rapsody, but was later also included in the final track list. The album version includes Jurin, Maya, Harvey, and Cocona.
