Game Development Reference
In-Depth Information
A simple game such as rock-paper-scissors (or roshambo/rochambeau) is unpredict-
able because its outcome depends on the decisions made by the players. The rules
do not favor one choice or another; they do not suggest a particular strategy. Trying
to second-guess or influence the choice of your opponent might involve empathy
or reverse psychology, but it remains largely outside the individual player's control.
The classic board game
Diplomacy
uses a similar mechanism. In this game, players
control only a handful of armies and fleets. Victory in battle simply goes to the side
that committed the largest number of units to a battle. However, because all the
players write down their moves secretly and resolve their turns simultaneously, the
players must use their social skills to find out where their opponent will strike and
to convince their allies to support their offensive and defensive maneuvers.
When the rules of a game are complex, they can also make a game unpredictable,
at least to human beings. Complex systems usually have many interacting parts.
The behavior of individual parts might be easy to understand; their rules might be
simple. However, the behavior of all the parts combined can be quite surprising and
difficult to foresee. The game of chess is a classic example of this effect. The move-
ment rules of the 16 chess pieces are simple, but those simple rules produce a game
of great complexity. Whole libraries have been written about chess strategies. Expert
players try to lure opponents into traps involving many pieces that might take mul-
tiple turns to execute. In this type of game, the ability to read a game's current state
and understand its strategic complexities is the most important game-playing skill.
Most games mix these three sources of unpredictability. They include an element of
chance, player choices,
and
complex rules. Different players prefer different com-
binations of these techniques. Some like games that involve many random factors,
while others prefer games where complexity and strategy are key. Of these three
options, chance is the easiest to implement but not always the best source of unpre-
dictability. On the other hand, complex rule systems that offer many player choices
are dificult to design well. This topic will help you with that task. We devote most
of the chapters to designing rule systems that create, among other things, interest-
ing choices for players. In Chapter 6, “Common Mechanisms,” we cover random
number generators (the software equivalent of dice) and discuss them at several other
points as well, but we feel that chance serves a supporting, rather than a central,
role in mechanics design.
From Rules to Mechanics
The video game design community usually prefers the term
game mechanics
to
game
rules
because
rules
are considered printed instructions that the player is aware of, while
the mechanics of video games are hidden from the player, that is, implemented in
software for which the player is given no direct user interface. Video game players
don't have to know what the game's rules are when they begin; unlike board and card
games, the video game teaches them as they play. Rules and mechanics are related
concepts, but mechanics are more detailed and concrete. For example, the rules of
Monopoly
consist of only a few pages, but the mechanics of
Monopoly
include the
