Writer Jeff Lemire handles the dynamic between doctor and patient well. The book makes some effort at diagnosing Joker, casting him as a performance artist giving Gotham City the art it needs. At the same time, Lemire ensures Joker remains as inscrutable as ever, and the reader can never trust whether Joker believes a single word he's saying or is simply leading Arnell down a path of his choosing. The dynamic works because Arnell is, in his own way, just as inscrutable as Joker. He paints the picture of a bright, upwardly mobile family man, but his motivations are often called into question. Is he truly pursuing noble work or merely in it for the ego rush and recognition? And once Arnell begins hallucinating, his status as an unreliable narrator only grows.
Beyond that twisted dynamic between patient and doctor, it's the atmosphere that helps Killer Smile stand apart. And that's all thanks to Andrea Sorrentino, an artist with a particular skill for finding the surreal and unsettling side of any universe in which he works. Lemire's heavy blacks and strong sense of page design ensure the book maintains an unsettling, creepy tone that occasionally veers into outright terror. Sorrentino somehow manages to make Joker look more human and ordinary than normal while still presenting him as a sinister, dangerous figure.While much of this issue features Sorrentino working in his usual bleak style, he does take the opportunity to shake up that approach in certain sections. Flashbacks to Joker's earlier criminal rampages take on a much brighter tone. Lemire's thinner, tighter line-work and Jordie Bellaire's more saturated color palette helps set these scenes in stark contrast to the rest of the book. The tone is faux-cheerful, as the inhumanity of Joker's actions slowly worms its way into these idyllic scenes. Several pages also take the form of a children's storybook, another case of superficially lighthearted imagery carrying very sinister undertones. Once again, DC's Black Label line gives an artist the space and freedom to experiment and bring their best work to the table.