The document discusses different types of narrative enigmas or hermeneutic codes that are commonly used in thriller films. It defines the hermeneutic code as questions left unanswered at the beginning of a film that are important to the plot. Some examples of hermeneutic codes given are who the murderer is in a crime thriller or why the antagonist is wearing a mask. The document also discusses using proairetic codes, which involve foreshadowing future dramatic actions, to build suspense and tension in narratives. It provides an example of including a proairetic code in the opening sequence by having the antagonist text the protagonist to meet, hinting he is the next victim of serial killings.