Internal Economy - Game Mechanics: Advanced Game Design - page 67

minerals to build a mining unit (called an SCV, for Space Construction Vehicle) that
can be used to collect new minerals. If StarCraft players set aside a certain portion
of their mineral income to build new SCVs, they get the same curve as money in a
savings account.
FIGURe 4.7
Positive feedback
creates exponential
curves.
Obviously, StarCraft players do not spend their resources only on SCV units. They
also need to spend resources to build military units, to expand their bases, and to
develop new technology. However, the economic growth potential of a base in
StarCraft is vital in the long run. Many players build up their defenses first and
harvest many resources before pushing to destroy their enemy with a superior
capacity to produce military units.
deadlocks and mutual dependencies
Positive feedback mechanisms can create deadlocks and mutual dependencies. in StarCraft ,
to get minerals, you need scv units, and to get scv units, you need minerals. These
two resources are mutually dependent, and this dependency can lead to a deadlock
situation: if you are left without minerals and scv units, you can never get production
started. in fact, you need enough minerals and at least one scv unit to be able to build
a headquarters, a third resource that enables this feedback loop. This deadlock situation
is a potential threat. an enemy player might destroy all your scv units. if this happens
when you have spent all your minerals on military units, you are in trouble. it can also
be used as a basis for level design. Perhaps you start a mission with military units, some
minerals, but no scv units or headquarters. in this case, you must find and rescue scv
units. deadlocks and mutual dependencies are characteristics of particular structures
in mechanics.