[2][3] The reissue version of the album, titled End Theory: Final Edition, was released on March 30, 2022.

"[10] Younha wrote the lyrics, and sometimes the music, for most of the 11 songs;[13] among them, the selection of the title track fell on pop ballad "Stardust", as she thought it showed the preciousness and the importance of the process from a beginning to an end better than the others.

[12] The song, which talks about the precious beings met on planet Earth[9][14] and what true love is,[15] was composed by her best friend and member of composition team Urban Zakapa Kwon Sun-il, with Younha penning the lyrics, and started from the question "What kind of useful person am I?

[20] Son Gi-ho from IZM gave the album 4 out of 5 stars; he called it "intense" from the first track, stating: "All the songs in the album are sincere to capture both the person who rescued her and the music," and concluding "The light reached after countless attempts and failures gives Younha a chance to grow on her own and becomes a medium in the name of hope that will unite her and the public again.

"[1] Art Insight wrote: "Younha's End Theory doesn't erase the existence of sadness and failure from life, but looks straight ahead.