The document discusses how enigmas were used in the openings of several zombie films to engage audiences. It analyzes Dawn of the Dead, Resident Evil, and The Walking Dead in terms of the enigmas posed in their openings around how viruses spread, the identity and motivations of characters, and the fate of humanity. The use of enigmas is deemed suitable for the zombie genre as it scares audiences about future events and leads them to understand the gory nature of the films from the zombie conventions.