[1] "Killing" was written by Chung Ha and Jo Yoon-kyung, and composed by Musikality, Celine Svanbäck, Jeppe London, Mich Hansen, and Sam Merrifield.

Lyrically it compares the monotony and helplessness of life, particularly that caused by the COVID-19 pandemic, to a tunnel and speaks of the light at the end.

Lim Dong-yeop, writing for IZM, commented that the accompaniment and music "capture the overall atmosphere" and said that Chung Ha successfully conveys hope through "Killing Me".

[5] Angela Patricia Suacillo of NME praised the production, particularly the synth transition to an EDM chorus and the "sleek drop" that drives the vocals.

Suacillo also wrote that the combination of Chung Ha's vocals and the music video made for "a powerful track that speaks to the collective hurt for the times.