The film combines audio testimony from people involved in the case or who were familiar with Pinyan, "with speculative re-enactments that feature a mix of actors and actual subjects".

Zoo’s filmmakers intended to approach the film’s subject matter from a non-sensationalized perspective and chose to forego more lurid details, focusing instead on humanizing the people involved.

[4] Two Seattle-based filmmakers, Robinson Devor and Charles Mudede, curious about the type of people involved in the underground world of zoophilia, interviewed figures close to the case, including other members of the zoophile ring.

On their reasoning for wanting to make a documentary about the Enumclaw case, Robinson Devor and Charles Mudede said when the news story first broke in 2005, it quickly became a punch line in the media.

[1] Coyote, the only zoo that appears in the film, said he came to trust Devor to tell their story, saying "I felt in my gut he was not going to make an exploitive type of movie.

[1] Devor said the film’s biggest challenge was finding locations to shoot, as horse farms in the Seattle area did not want to be associated with the documentary.

The audio is the moans, grunts and gasps of Kenneth, the lubricant sounds of the sex, the ejaculation and two unidentified men making brief comments, with one engaging in erotic talk.

[6][7] Sundance judges called the film a "humanizing look at the life and bizarre death of a seemingly normal Seattle family man who met his untimely end after an unusual encounter with a horse".

[9] Rob Nelson of the OC Weekly said, "Zoo achieves the seemingly impossible: It tells the luridly reported tale of a Pacific Northwest Boeing engineer's fatal sexual encounter with a horse in a way that's haunting rather than shocking and tender beyond reason.

[12] Anthony Kaufman of IndieWire called it "one of the most beautiful films of the year" and noted that "without sensation", it steps back to a "non-traditional" viewpoint, with "Devor [making] a persuasive, provocative and deeply profound case for tolerance and understanding in the face of the seemingly most incomprehensible of acts".