Gameplay - Fundamentals of Game Design - page 274

challenge requires that the player know not only the capabilities and vulnerabili-
ties of her units but also those of the entity she must protect. She must be prepared
to sacrifice some units to protect the vital one.
STEALTH
The ability to move undetected, an extremely valuable capacity in almost any kind
of conflict, especially if the player takes the side of the underdog, can form a chal-
lenge in its own right. Games occasionally pose challenges in which the victory
condition cannot be achieved through combat but must be achieved through
stealth. Thief: The Dark Project was designed entirely around this premise. It
required players to achieve their missions by stealth as much as possible and to
avoid discovery or combat if they could.
Stealth poses a considerable problem in the design of artificial opponents for war
games. In a game with no stealth, the AI-driven opponent has access to the com-
plete state of the game world; to include stealth, you must restrict the opponent's
knowledge, limit its attention, leave it ignorant of whole regions of the game world.
You decide what the AI opponent does and doesn't k now and define what steps it
takes, if any, to gain further information.
Economic Challenges
An economy is a system in which resources move either physically from place to
place or conceptually from owner to owner. This doesn't necessarily mean money;
any quantifiable substance that can be created, moved, stored, earned, exchanged,
or destroyed can form the basis of an economy. Most games contain an economy of
some sort. Even a first-person shooter boasts a simple economy in which the player
obtains ammunition by finding it or taking it from dead opponents and consumes
it by firing his weapons. Health points are also part of the economy, being con-
sumed by hits and restored by medical kits. You can make the game easier or harder
by adjusting the amount of ammunition and number of medical kits so that a
player running short of firepower or health must carefully manage his resources.
The behavior of resources, as defined by the core mechanics of the game, creates
economic challenges. Some games, such as SimCity , consist almost entirely of eco-
nomic challenges. Such games tend to have flattened challenge hierarchies in
which the atomic challenges appear similar to the overall goal of the game. Other
games, such as first-person shooters, combine economic challenges with others
such as conflict and exploration. Chapter 10, “Core Mechanics,” addresses the
internal economies of games at length.
ACCUMULATING RESOURCES
Many games challenge the player to accumulate something: wealth, points, or any-
thing else deemed valuable. Acquisition of this kind underlies Monopoly and many