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 cant 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 Systems A 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.

T room = + F(T room – T thermostat ) In Other Words: T room = – F(T room – T thermostat ) Or… F(x) is any increasing function.

Feedback Systems in Games Game State Scoring Function Controller Game Mechanical Bias

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: S me = – F(S me – S you ) F(x) is any increasing function S me and S you are the two teams scores. Or… S me = + F(S me – S you )

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. Theres 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 Structure

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 Dont 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? www2.lglass.com/~mahk Shameless Plug: GDC 2000 Formal Design Tools: Emergent Complexity, Emergent Narrative