("Dressing" redirects here)
According to Jesper Juul in his book Half Real, a game's fiction is the narrative world that is created through dialogue, graphics, narration, etc. It is complementary to or at odds with the game's rules, and helps create the experience of gameplay.
When the rules of a game (such as multiple lives) contradict the laws of its fictional world, the coherence of the game is brought into question. However, the fact that completely incoherent games may be played leads Juul to claim that the fiction of the game is "optional," and not an essential part of gameplay. Juul takes the ludologist position when he claims that although games can tell stories, they are not "simply storytelling media," and contain rules which may very well stand on their own (161).
Similarly to Juul, designer Raph Koster calls the fictive context of a game the "dressing" in his book A Theory of Fun for Game Design. This is separate from the actual system of the game, the rules and goals.
For example, in chess, the pieces are named in order to evoke a conflict between two royal families, with pawns, rooks, and knights charging into battle or engaging in political intrigue (depending on how you take to the metaphor.) While the "dressing" has no effect on the gameplay per se, it definitely changes the overall experience of a game. As the dressing is what people tend to see rather than the underlying abstract system of a game, it is the element often criticised by the media or at least deemed controversial.
Schell's Story and Transmedia WorldsEdit
Game designer Jesse Schell discusses fiction in a slightly different way in The Art of Game Design: A Book of Lenses. To Schell, a game's story is one part of what he calls the Elemental Tetrad, and is just as influential in shaping the player's experience of the game as the element of mechanics is. In addition, story can be seen as a gateway into the transmedia world surrounding the game, which includes books, television shows, and action figures (Schell 301). Schell provides Pokemon as an example of a very successful transmedia world.