FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
Layouts
For games that involve travel, especially avatar-based games, the layout of the space significantly affects the player's perception of the experience. Over the years, a few common patterns have emerged, which this section introduces in simplified form. You should not hesitate to create any layout that your game needs.
In an open layout, the player benefits from almost entirely unconstrained movement. An open layout corresponds to the outdoors, with an avatar in principle free to wander in any direction at any time. Even levels with open layouts, though, may include a few small regions that cannot be entered without difficulty or can be entered by only a single path (such as passing through a door into a building). War games make extensive use of open layouts, Battlefield 1942 being a particularly successful example. Role-playing games offer open layouts while the player goes adventuring outdoors, but they typically switch to network or combination layouts (described later) when the party goes indoors or underground.
A linear layout requires the player to experience the game's spaces in a fixed sequence with no side corridors or branches. It does not mean that the spaces are actually arranged in a line (see Figure 12.1). A player following a linear path can move only to the next area or to the previous area and does not have to make any decisions about where to go next. A game in which all levels use linear layouts is often said to be on rails because, like a train on a track, the traveler goes wherever the predefined route takes her. Ordinarily, the player has no reason to go backward in a linear layout unless she forgot to pick up something that she needs. Linear layouts often require players to pass through one-way doors that actually prevent them from going back, so long as they have collected everything they need to go on. Be sure you don't lock a player out of a region that contains an item essential to her later progress—an elementary level design error.
Linear layouts naturally work well with linear stories; if your game features such a story, you might consider such a layout. See Chapter 7, "Storytelling and Narrative," for more on linear stories.
Traditional for side-scrolling action games and rail-shooters, the linear layout is otherwise uncommon nowadays. Today's designers tend to favor the parallel layout.
