The novella has gained critical praise for its "lyrical" prose and for the illustrations in the United States version, done by artist Andrea Offermann.

This is not a chronological telling but the narrative events come to us almost like a play, with limited settings, such as glimpses of the boys’ travels, the zoo, and the Rom camp.

Symbolic meanings are fundamental to understanding the narrative: its time frame, the survival of the zoo, its midnight setting.

The Midnight Zoo received positive reviews from critics, mostly for the "lyrical" prose and the illustrations from Andrea Offermann in the American version.

[2] Publishers Weekly gave it a starred review and said that Harnett "mak[es] a profound case for the futility of war while exploring questions about responsibility and freedom.