Formal Design Tools

Feedback Systems

and the Dramatic Structure of Competition

A rant by MAHK

GDC 1999

Game Design Fortune Cookies

• “Aimless wandering is the enemy of fun.”

• “Hardship is not the same as gameplay.”

• “Create compelling illusions, not realistic simulations.”

• “Know your roots.”

• “50,000,000 Elvis fans can’t be wrong.”

The Alternative: Formal Design Tools

• Rules, Models, Techniques

• Well-defined

• Abstract (i.e. cross-genre)

• Day-to-day utility

• Well-understood application context

• Lenses, not value statements

Lecture Overview

• Context: Competitions

• Feedback Systems– Definition– Positive & Negative Feedback– Application to Games

• Dramatic Structure – Definition– Application to Games– Drama-Creation Techniques

Obligatory Disclaimers

• This is really pointy-headed.

• There will be math.

• No LaPlace transforms; No game theory.

• This may be review.

• Leave now.

Part 1: Feedback SystemsA feedback system monitors and regulates its own output.

Room

Too Cold

Too Hot

Example: An Ideal Thermostat

Thermometer

Controller

Cooler

Heater

The Thermostat System is Negative Feedback

• Reduces the difference between the actual temperature and the target temperature.

Negative Feedback Systems:

• Drive their output towards a target value.

• Keep their output within an acceptable range.

• Are stable.

Positive Feedback

Room

Too Cold

Too Hot

Thermometer

Controller

Cooler

Heater

Example: The Evil Anti-Thermostat

Positive Feedback Systems:

• Drive their output away from the “target” value.

• Left to their own devices, will drive their output to infinity.

• Are unstable.

Troom = + F(Troom – Tthermostat)

In Other Words:

Troom = – F(Troom – Tthermostat)

Or…

F(x) is any increasing function.

Feedback Systems in Games

Game State “Scoring Function”

ControllerGame MechanicalBias

Example: Negative Feedback Basketball

For every N points of difference in the two teams’ scores, the losing team may have an extra player in play.

Laptop Motivation Slide

This is the point in my talk where my laptop crashed at the GDC in march.

A round of encouraging applause, please, to my laptop, for making it this far.

Positive Feedback Basketball

For every N points of difference in the two teams’ scores, the winning team may have an extra player in play.

In Other Words:

Sme = – F(Sme – Syou)

F(x) is any increasing function Sme and Syou are the two teams’ scores.

Or…

Sme = + F(Sme – Syou)

Feedback Rule #1

• Negative feedback stabilizes the game.

• Positive feedback destabilizes the game.

• Stability is game balance.

Feedback Rule #2

• Negative feedback forgives the loser.

• Positive feedback rewards the winner.

Feedback Rule #3

• Negative feedback can prolong the game.

• Positive feedback can end it.

Feedback Rule #4

• Positive feedback magnifies early successes.

• Negative feedback magnifies late ones.

The Most Common Example: The Intrinsic Negative Feedback

in Many-Player Games

“Everybody gang up on the scourge!”

Other Feedback Examples

• Battle Arena Toshinden: desperation moves (negative)

• Civilization: exponential growth (positive)

• Wing Commander: system damage (positive)

One More Example: An Auto Racing Game with Guns

• Front-mounted guns: negative feedback

• Rear-mounted guns: positive feedback

Feedback Rule #5

Feedback systems can emerge from your game systems “by accident.”

Be sure to identify them.

• Many-player games• Simulations

Feedback Rule #6

When two different feedback systems are in conflict, one will overwhelm the other.

• There’s no equilibrium

• Small biases matter

Feedback Rule #7

Players are stabilizing influences.

The player who is ahead:

• Sandbags

• Gets lazy

• Has too many options

Feedback Rule #8

Feedback systems can take control away from the players.

Feedback Summary

• Feedback systems exist in games– Negative feedback stabilizes the game.

– Positive feedback destabilizes the game.

– Some feedback systems are emergent.

– Both positive and negative feedback are useful to game designers.

On to Part 2...

Part 2: Dramatic StructureD

ram

atic

Ten

sion

Narrative Time

Conflict Resolution

Climax

Dramatic Structure

• “Formal tool for narrative design.”

• Competition can have dramatic structure.

• Some games have both competition & narrative.

Dramatic Structure In Games

• Creates a sense of “wholeness.”

• Provides a larger context for small decisions.

• Creates games that make good stories.

What Creates Dramatic Tension?

• Competition is Conflict.

• Uncertainty: The winner is unknown.

• Inevitability: – Resolution is imminent.– The game is moving forward.

Dramatic tension does not guarantee dramatic structure.

Dramatic Structure Examples

• Basketball (organized vs. pick-up)– Clock creates inevitability

• Magic: The Gathering– Deck, Mana create inevitability.

• Deathmatch– Small-scale drama in each confrontation– No overall structure

Creating Inevitability

• Approach the end of the game through:– A non-reversible process.– A non-renewable resource.

Creating Uncertainty

• We want the game to feel close.

• Thus, negative feedback systems can induce uncertainty.

• Other stabilizing forces also work.

Timing the Climax

• Too Early: – Too much time spent knowing who will win.– Players become spectators.

• Too Late:– End of game takes the players by surprise.– A moment of realization is necessary.

Timing the Climax

In games, the climax comes relatively late, because:

• Again, competition is conflict.

• It does in narrative.

• Some resolution occurs after the game ends.

Resolving Dramatic Tension

• Maintain the same sense of inevitability (i.e. the same non-reversible process.)

• Replace uncertainty with certainty, through de-stabilizing forces (e.g. positive feedback).

Example: Basketball

• Negative feedback moves climax later.

• Positive feedback moves it earlier.

Example: StarCraft

• Uncertainty– Fog of War

• Inevitability – Finite raw materials– Time is a resource

• Uncertainty erodes over time.

• Exponential growth eventually destabilizes.

Example: Titan

Details:– “Build & Conquer” game– Fighting costs units (attrition).– Winning fights earns units & power– Attrition remains constant, but rewards

increase.

Example: Titan• Early game:

– Costs outweigh rewards– Stable & uncertain

• Late game:– Rewards outweigh costs– Unstable & certain

• Weak sense of inevitability.

Example: FireTeam Deathmatch

Details:– Deathmatch with teams.– Phase 1: Infinite resurrection, earn lives.– Phase 2: Finite resurrection, spend lives.

(Phase 2 has positive feedback)

Example: FireTeam Deathmatch

• Inevitability– Time limit

• Uncertainty– Phase 1 is stable & uncertain– Phase 2 is unstable & certain

• Phase 1 is longer than Phase 2; late climax

Example: You Don’t Know Jack

• Uncertainty– Questions increase in value over time.– High-Scoring bonus rounds late in the game.

• Inevitability – Fixed game length

• Can easily climax too early

• Random feedback elements

A Newtonian Metaphor

• Dramatic Tension = Potential Energy

• Stabilizing/Destabilizing Forces = Force

• Forward Progress = Distance

Dramatic Structure Summary

Games can benefit from dramatic structure.– Non-reversible processes create inevitability.– Stabilizing forces create uncertainty.– Resolve the tension you create.

Questions?

mahk@lglass.com

www2.lglass.com/~mahk

Shameless Plug: GDC 2000Formal Design Tools:

Emergent Complexity, Emergent Narrative