FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
. Shell Menus and Screens
Whenever the player is taking actions that influence the game world, that is, actually playing the game, the game is in a gameplay mode. However, most games also have several other modes in which the player cannot affect the game world, but can make other changes. These modes are collectively called shell menus because the player usually encounters them before and after playing the game itself (they are a "shell" around the game, outside the magic circle). Examples of the kinds of activities available in a shell menu include loading and saving the game, setting the audio volume and screen resolution, and reconfiguring the input devices for the player's convenience. A pause menu in a game is also a shell menu unless it lets the player take some action that affects the game world (such as making strategic adjustments in a sports game), in which case it is a gameplay mode. Noninteractive sequences such as title screens or credits screens are called shell screens.
The gameplay modes and shell menus of the game, and the relationships among them, collectively make up the structure of the game. For example, in a car racing game, driving the car into the pit causes the game to switch from the driving mode to the pit stop mode. When the work of the pit crew is finished, the game switches
back to the driving mode. Pressing the Start button on the controller while driving brings up a pause menu, and so on. You need to document these details for the rest of the development team.
To document the structure, you can begin by making a list of all the modes and menus in the game. You must also include a description of when and why the game switches from one mode or menu to another: what event, or menu selection, causes it to change. Each mode or menu description should include a list of other modes and menus it can switch to and, for each possible switch, a notation about what causes it.
You can document the relationships among all the modes and menus by simply listing them all in a text editor. However, the result isn't easy to follow. A better approach is to document the structure of a game with a flowboard, a combination of flowchart and storyboard. This type of diagram is described in the section "Flowboard," later in this chapter.
Normally, a game moves among its shell menus in response to player actions and nothing else, although arcade games often display an attract loop that repeatedly shows a title screen, a short noninteractive video of a game in progress, and a high score table. During actual play, a game changes from one gameplay mode to another in response to player actions, or automatically as the circumstances of the game require. For example, in a soccer game, certain violations of the rules result in a penalty kick, in which a single athlete on one team tries to kick the ball past the opposing team's goalie and into the goal and the other athletes on both teams play no role. This is clearly a gameplay mode different from normal play. The game enters the penalty kick mode not in response to a specific player choice but because a rule has been violated.
