The film was among the first to embody the idea that, in horror, less is more. And while the film is credited as one of the earliest films noir, few critics have ever traced its lineage back to the German Expressionism of the 1920s, in films like Nosferatu, Symphony of Horror by F.W. Murnau, The Cabinet Of Dr. Caligari by Robert Wiene, or Metropolis by Fritz Lang.

Yet, the film could easily be camp itself, were it not for the superb acting of all involved, especially Simon. At times vacant, passionate, disinterested, hurt, she embodies a naïf sexuality that few men can resist. Kent Smith is stiff, but in the best sort of way, as the affably satisfied Oliver, who seems so boring that it's hard to believe two beautiful women would desire such a bore and wimp. Jane Randolph is very good as well, as a subtle manipulator of events, such as telling Oliver she loves him in a seductive voice when he confides in her of Irena's problems.

But, the film's real scene stealer is Tom Conway, as the lascivious Dr. Judd. He's believable as the parasitic doctor who gets his comeuppance. He was also the real life brother of actor George Sanders, who played a similarly smarmy role, as Jack Favell, in Alfred Hitchcock's Rebecca. The rest of the minor characters are also rounded out into believability; a rarity, even for A films of any era. Most notable are Alex Craig as the fearful zookeeper, Jack Holt as The Commodore, and Alan Napier (who would later play Alfred the butler on the 1960s TV show Batman) as Carver, a coworker of Oliver's and Alice's. Even a black female coffer server at the coffee shop is shown wearing a headwrap, but she's shown as a real person, not a mammy.

There are also many memorable scenes, such as the reaction of animals to Irena — like a kitten Oliver buys her, then all the animals at the pet shop when they return it. They get a canary, but it dies of fright when Irena sticks her hand in the cage, as if a cat's paw, and the look of sadistic glee on her face is priceless, as is the change to depression when she realizes what she has done. She then tosses the dead bird to the panther at the zoo, which is not far from her apartment. There she listens to the big cats howl at night. This makes one wonder how a foreign sketch artist could afford to live in such luxurious digs, as her Manhattan apartment is huge, and in one of the priciest areas in town.

Another well wrought scene, and also famous is when, at her wedding reception at a local eatery, a nameless cat-woman, (Elizabeth Russell) approaches Irena and addresses her, in Simon's dubbed vocals, as 'my sister,' in Serbian. Another great scene is Irena's nightmare with cartoon panthers and Dr. Judd as King John.