[13][14] The title track "Girls Never Die" delivers "early 2000s dance grooves" with synth and bass.

"Midnight Flower" is bubbly pop rock song[14] with a foundation of beats and guitars reminiscent of the 1980s.

It received praise for its diverse range in genre, which Han Seong-hyeon, writing for IZM, expressed as TripleS bringing "music from all over the world to the center of Seoul".

[13] Raul Stanciu of Sputnikmusic described it as a "successful blend" of their previous music, observing some similarity to Loona in the "bubbly, retro futuristic synth pop with occasional RnB type vocals".

[15] Rhian Daly, writing for NME, characterized Assemble24 as "wide-ranging yet cohesive" with each track designed to fit TripleS.