Game Development Reference
In-Depth Information
Dominant Strategies in Video Games
Video games seldom permit players to use strategies so strongly dominant that
they absolutely guarantee victory, although some, whether PvP or PvE games,
allow powerful strategies that give the player little reason to use any other. By far
the best-known dominant strategy in any PvP video game is the tank rush in
Westwood's
Command & Conquer: Red Alert.
An experienced player playing as the
Soviet side can devote all of his energies to producing a large force of tanks in the
early part of the game, then use those tanks to attack the nascent enemy base en
masse. Against an unprepared opponent, this almost always produces a victory; an
experienced opponent can prepare for the onslaught, but the tank rush remains so
effective that it takes the fun out of the game. Many players add an additional rule
to the game—no tank rushes allowed—just to balance this problem.
Several editions of
Madden NFL
included unstoppable offensive plays that guaran-
teed success against an AI-controlled opponent. Fighting games, too, are especially
prone to dominant strategies. In both fighting games and football games, the large
numbers of possible combinations of offensive and defensive actions makes it diffi-
cult to test them all. Badly designed characters can also result in dominant strategies;
in
Super Street Fighter II Turbo
, the secret character Akuma's unbeatable attack, the
air fireball, leaves the rest of the characters with no chance. Tournament matches
ban the use of Akuma to ensure fair play.
The next few sections discuss ways that dominant strategies can emerge in a video
game and how to avoid them or remove them by using balancing methods.
TRANSITIVE RELATIONSHIPS AMONG PLAYER OPTIONS
The term
transitive
describes a relationship among three or more entities so that if
A stands in a certain relationship to B, and B stands in the same relationship to C,
then A stands in the same relationship to C also. If you may correctly draw this
conclusion, the relationship displays a property called
transitivity
.
Greater than
in
arithmetic provides an example of a transitive relationship: If A is greater than B,
and B is greater than C, then A is greater than C.
If a transitive relationship exists among a player's strategic options, then option A is
better than option B, and option B is better than option C. Why, then, would a player
ever use option C? Selecting option A becomes a dominant strategy. To use a con-
crete example, if you design a game so that an aggressive strategy is always better
than a defensive one and a defensive strategy is always better than a stealthy one, a
smart player always chooses the aggressive strategy—it is superior to all the others.
To correct this imbalance, you may impose direct costs on using each strateg y, costs
that counteract the superiority of the stronger strategies and so give players a rea-
son to consider the (formerly) weaker strategies as well. To draw an analogy, a lot of
kids who would like to ride horses have to ride bikes instead because, even though
horses are more fun to ride, they cost a lot of money.
