Game Design
10
Game System Dynamics
A Tale of Epidemics
• It all started from an infected pet brought into a large population center
• The disease was terrible
– It could kill in seconds
– Others were infected but asymptomatic, thus spreading the disease
A Tale of Epidemics
• People started to run away from large cities, and spread the illness to more remote areas
– Quarantines were set up, but not heeded – Some people tried to help
• They ended up becoming infected as well
– Some others spread the infection intentionally
• The dead started to pile up
A Tale of Epidemics
• And finally…
• Blizzard hard reset the servers and it was all
good
13
thSeptember 2005
• World of Warcraft
– Zul Gurub, a high level dungeon
Corrupted Blood
• The final boss, Hakkar the Soulflayer, cast a debuff
– Transferred by a dismissed pet to Stormwind
Corrupted Blood Incident
• In addition to inflicting severe damage on the target character, the disease “infected” close contacts who could spread the disease to
others in close proximity. [1]
– Presumed the short period of infectivity (several seconds), as well as its highly lethal effect, would render the disease self-limiting.
Corrupted Blood Incident
• Uncontrolled dissemination of the disease[1]
– lack of residual immunity
– infectivity to the virtual animals – characters could teleport
– nonplayer characters of the city also spread the disease.
• Numerous scholarly articles analyzed the
event
What Are Games Made Of?
• Formal Elements – define the structure of a game
– Players, Objectives, Procedures, Rules, Resources, Conflict, Boundaries, Outcome
• Dramatic Elements
– Challenge, Play, Premise, Character, Story, World Building, The Dramatic Arc
• System Dynamics
– Games as Systems, System Dynamics, Interacting with Systems, Tuning Game Systems
System Dynamics
• A system[2]
– “A set of interacting elements that form an
integrated whole with a common goal or purpose”
• Purpose of system dynamics in games[2]
– system principles for the quality of interactions and growth and change over time.
Games Are Systems
• A game is a set of formal elements which create a dynamic experience for players
– The interaction between formal and dramatic elements shapes the player experience
System Elements[2]
• Objects
• Properties
• Behaviors
• Relationships
Objects
• Basic bricks of your system
– Game pieces – Items
– Players
– In-game concepts – Etc.
• Defined by behaviors and properties
Properties
• Values that define aspects of objects
– Lvl. 12 Human Female Mage
• Values for attributes
• Properties are important for determining interactions and relationships
– The more complex the properties, the less predictable the relationships
Behaviors
• Possible things an object might do in a given state
– As with properties, the more complex the
behavior, the less predictable the interaction
Relationships
• Define the manner in which objects interact
– Can be expressed in different ways
• Linear
• Hierarchical
• Fixed
• Variable
• Etc.
Relationships
• Gladia
– Lvl. 2 Paladin with 18 strength (+4 bonus) – Attacks a goblin with 13 AC
– To hit, she needs to roll a D20, add proficiency (2) and STR bonus (4) and get at least 13
• Hits 70% of the time
System Dynamics
• Elements are not isolated from each other
– All elements are needed for a system to work – Elements need to be arranged in a specific way,
too
• Changes any of the above will have an effect on your game
System Dynamics
• Systems are greater than the sum of their parts
– Examining the pieces in isolation will NOT be the same as studying the complete system
• Because of this
– Games can only be understood when played – We cannot determine player experience, only a
potential set of outcomes
Economies in Games
• When does a game have an economy:
– Items to exchange
– Agents to exchange them – Currency (optional)
– Pricing (fixed or variable) – Market limits
Economies in Games
• Creating an in-game economy [2]
– Does the size of the economy grow?
– How is the supply of currency controlled?
– How are prices set?
– Is there any restriction on trade?
Emergent Gameplay
• Systems which generate unexpected results
– Game of Life (John Conway)
• Played on a checkerboard
• Birth: If an unpopulated cell is surrounded by exactly three populated cells, it becomes populated in the next
generation.
• Death by loneliness: If a populated cell is surrounded by fewer than two other populated cells, it becomes
unpopulated in the next generation.
• Death by overpopulation: If a populated cell is surrounded by at least four other populated cells, it becomes
unpopulated in the next generation.
Emergent Gameplay
• Use emergent techniques to make games more believable
– E.g. semi-realistic behavior for NPCs
• GTA and RDR - Agents perceive elements of their environment and act upon them
Interacting with Systems
• We are building games, after all
– Games require interaction
– In order to interact, players also require information and feedback
Interacting with Systems
• When building interactions, consider the following [2]
– The information available to the player regarding the state of the system
– What parts of the system are under player control – What feedback the systems provides
– How the above are aggregated into gameplay
