Storytelling and Narrative - Fundamentals of Game Design - page 170

is, you present a nonlinear story—you introduce the risk of error. The storytelling
engine must guarantee that the events make sense. If the player wrecks a car during
play in a game with a nonlinear story, the storytelling engine must ensure that the
game does not present any subsequent gameplay or narrative material that shows
the car undamaged. If you're not careful, you can introduce what the film industry
calls continuity errors: things that look different from the way they should look,
given the events of preceding scenes, because narrative material can't change to
keep up with game events. Linear stories don't incur this risk. If a car is wrecked as
part of the story, it stays wrecked; if it mustn't be wrecked, then you must not give
the player any way to wreck it.
Linear stories deny the player agency. The player may have freedom to do a lot
of things in the game, but none of it influences the story apart from causing it to
progress. As the previous consideration said, if the story requires a functional car
throughout, then the gameplay cannot allow the player to wreck the car. The sec-
tion “Endings,” later in this chapter, discusses this issue in more depth.
Linear stories are capable of greater emotional power. From a creative stand-
point, this is one of their greatest advantages. The section “Emotional Limits of
Nonlinear Stories” explains this point in more detail later in this chapter.
Note that if you want to tell a strictly linear story, that decision will have conse-
quences for any story you plan to treat as a journey (as many are). See the section
“The Story as a Journey” later in this chapter.
Nonlinear Stories
If you allow the player to influence future events and change the direction of the
story, then the story is nonlinear. This chapter examines two of the most common
structures for nonlinear stories— branching stories and foldback stories —in detail in
the next two sections. A third approach, emergent narrative , is more of a research
problem than a standard industry mechanism, and we'll discuss it briefly. After
that we'll look at a new hybrid technique that shows great promise for the future of
interactive storytelling. Finally, we'll study an important issue for any teller of non-
linear stories: How many endings should the story have?
Branching Stories
A branching story allows the player to have a different experience each time he plays
the game. The story offers not one plot line but many that split off from each other
at different points. As the designer, you decide on the different possible plot lines
and how they relate to each other. During play, the storytelling engine keeps track
of which plot line the player is following at any given time. When the story reaches
a branch point —a place where the current plot line subdivides—the core mechanics
must send a trigger to the storytelling engine to tell it which of the possible
branches of the story the player will follow next.