FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
DESIGN RULE Randomness and Repetition Destroy Dramatic Tension
The narrative events in a game's story must not occur randomly or arbitrarily, nor should the narrative repeat itself, even if the play itself is repetitive.
To design a game that includes a story, you must interweave the gameplay—the actions taken to overcome the game's challenges—with the narrative events of the story. Narrative events must be interspersed among the gameplay events in such a way that all events feel related to each other and part of a single sequence that entertains the player. If the gameplay concerns exactly the same subject matter as the narrative—and it should, in order to present a coherent and harmonious whole—then the entire experience, play and narrative together, will feel like one continuous story.
The storytelling engine does the weaving. Chapter 2, "Design Components and Processes," introduced the storytelling engine briefly as the third major component of a video game along with the core mechanics and the user interface. Unlike the other two, the storytelling engine is optional; if the game doesn't tell a story, it doesn't have a storytelling engine.
Just as the core mechanics generate the gameplay, the storytelling engine manages the interweaving of narrative events into the game. The core mechanics oversee the player's progress through the game's challenges; the storytelling engine oversees the player's progress through the game's story. The storytelling engine and core mechanics must work together to create a single, seamless experience.
Figure 7.1 illustrates the relationship between the storytelling engine, core mechanics, user interface, and player. Notice that Figure 7.1 resembles Figure 2.1 from Chapter 2. Figure 2.1 showed how the core mechanics produce and manage gameplay. Figure 7.1 shows how both the core mechanics and storytelling engine together produce the experience of interacting with a story.
As the section "Interactive Stories" explained earlier, an interactive story contains three types of events: player events, in-game events, and narrative events. The core mechanics manage the player events and in-game events, as the figure shows. The storytelling engine manages the narrative events. However, the storytelling engine does more than just play movies or cut-scenes; it also keeps track of the progress of the story and determines what part of the plot should come next.
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Notice that a double-headed arrow labeled Triggers connects the storytelling engine to the core mechanics in Figure 7.1. At times, the core mechanics may determine that the interaction should stop and the storytelling engine should present some narrative—for instance, when a player completes a level. The core mechanics send a message to the storytelling engine saying that the player finished the level and the storytelling engine should now display any interlevel narrative events. Likewise, the storytelling engine can send a trigger back to the core mechanics when a narrative event finishes (or when the player interrupts a narrative event), telling the core mechanics to resume play.
The storytelling engine doesn't sit idle during play, however. As the player progresses, the mechanics continually send triggers to the storytelling engine—that way, the storytelling engine can keep up with what's going on. If, for example, the player makes a key decision that will affect the story later on, the core mechanics inform the storytelling engine of the decision.
Similarly, during play the storytelling engine can determine that the story has reached a critical plot point and trigger the core mechanics to cause changes to the internal economy of the game. Suppose the story says, "When the avatar reaches the bridge, he will be attacked by a highwayman in a cut-scene and robbed of all his property." The core mechanics, tracking the player's progress through the game world, send a message to the storytelling engine, "The avatar has reached the bridge." The storytelling engine detects that this is a key point, halts play, and displays a cut-scene showing the robbery. Then it transmits a message back to the core mechanics saying, "Transfer the avatar's inventory to the highwayman and resume play."
Normally, the level designers do the work that actually implements such events in the game. Among the level designer's tools for level-building will be a mechanism
for detecting the avatar's position and for triggering both the cut-scene and the transfer of the avatar's property. At the moment, a development company cannot license a storytelling engine from a middleware company the way it can license a graphics engine or a physics engine, but that may change. Still, at a conceptual level it will help you to design the story and its interaction with the gameplay if you think of these events in terms of triggers sent between the two separate components, the core mechanics and the storytelling engine.
As you can see, the storytelling engine plays a critical role in weaving the gameplay and narrative together to create the whole experience. The rest of this chapter refers to the storytelling engine frequently.
