Fundamentals of Game Design Game Balancing

1. Presented at the University of Winnipeg, Canada Just E.T.C for Business, Education, and Technology Solutions Fundamentals of Game DesignGame Balancing sayed@justetc.net Www.JustETC.net Sayed Ahmed BSc. Eng. in CSc. & Eng. MSc. in CSc. http://sayed.justetc.net http://www.justETC.net

2. Introduction • To be enjoyable • A game must • Be well balanced • Be not too easy nor too difficult • Feel fair to competing players • Feel fair to the individual player itself sayed@justetc.net Www.JustETC.net

3. Topics • Qualities of a well balanced game • How to balance your game • How to set up and balance both • Transitive and intransitive relationships among player choices • Make them simultaneously • Interesting and well-balanced • Dominant strategies and how they affect balancing • Ways to incorporate chance into games • Where the better player still enjoy better rewards • Will focus on two major issues of game balance • Fairness and difficulty • Fairness • Player versus player • Player versus environment sayed@justetc.net Www.JustETC.net

4. Topics • Difficulty • Player versus environment • Various factors that affect the player’s perception of difficulty • How to manage the factors • Role of positive feedbacks • How to use it • How to control it • Investigate the problems of • Stagnation • Trivialities • Design games so that the tuning stage is still easier sayed@justetc.net Www.JustETC.net

5. What is a Balanced Game • Balanced Game • Fair to the player (players) • Neither too easy nor too hard • Skill of the player is the most important factor to win the game • What makes a balanced game • Several different features together make the game balanced • A collection of design and tuning process create those balancing qualities in a game sayed@justetc.net Www.JustETC.net

6. What is a Balanced Game • Techniques for balancing may differ for • Player versus player (may be artificial opponent) • Player versus environment • A well balanced game posses the following characteristics • The game provides meaningful choices • The role of chance is not that extreme that player skill becomes irrelevant • Well balanced PvP posses the following • The players perceive the game to be fair • Any player who falls behind early in the game gets reasonable opportunities to catch up again before the game ends • The game seldom or never results in a stalemate sayed@justetc.net Www.JustETC.net

7. What is a Balanced Game: PvE • A Well Balanced PvE game posses the following • The player perceives the game to be fair • The game’s level of difficulty must be consistent sayed@justetc.net Www.JustETC.net

8. Avoiding Dominant Strategies • What is a strategy • The plan to play the game for victory • Can be aggressive • Can be defensive • Two player may prefer two different strategy • Ideally, they should have equal chance of winning • Dominant Strategy • A strategy that results the best outcome • A player may achieve • No matter what her opponent does • Are undesirable – makes all other choices useless • Worse: if one player can use the strategy – others cannot • Happens in asymmetric games • Makes the game unfair sayed@justetc.net Www.JustETC.net

9. Avoiding Dominant Strategies • One single choice can be a dominant strategy • Strategies that avoid loss or prevent an opponent from scoring points • May qualify as dominant • Before 1955, a basket ball player could use endless tactics - dominant sayed@justetc.net Www.JustETC.net

10. Dominant strategies in Video Games • Some video games permit dominant strategies • Command and Conquer: Tank Rush • Madden NFL • Fighting games prone to dominant strategies • Fighting and football games • Large number of offensive and defensive actions • Difficult to test (for fairness and balancing) • Bad character design may lead to dominant strategies • Super street fighter II turbo • Akuma: Air fireball sayed@justetc.net Www.JustETC.net

11. Transitive relationships among Player Options • Transitive • Relationship among three or more entities • A> B, B>C, A>C • Example: Strategic options • Aggressive > Defensive > Stealth • Aggressive > Stealth • Smart player will always choose Aggressive mode • To address the imbalance • You may assign direct costs to each strategy • That may lead to players to consider the weak strategies as well • Riding horse may be more fun but costlier than riding bi-cycle • Traveling with a Hummer will cost more than travelling with Ford • Shadow cost • PvE players find shadow costs are unfair • Designers use transitivity to reward players as well • Can be back and forth sayed@justetc.net Www.JustETC.net

12. Intransitive relationships • Here the relationships among strategies, or options are intransitive • A beats B, B beats C, • Does not mean that A beats C • Rock->paper->Scissors • Paper beats rock, rock beats scissors, scissors beat paper • Balanced three way intransitive relationship • Classic design technique to avoid dominant design strategies • Forms the basis for balancing player strategies in many games • Virtua Fighter 3 (David Sirlin) uses RPS for players movements • Attacking beats throwing, throwing beats blocking, blocking beats attacking • The ancient art of war: RPS three unit types: Knights, Archers, Barbarians • K>b, b>a, a>k sayed@justetc.net Www.JustETC.net

13. Intransitive relationships • RPS simple • Not suited to modern war games • Offers no interesting choices • Needs some variation • Adjust system to produce different benefits • Give players different amount of money to win with • Rock, paper, or scissor • Target to earn the most money • So make your choices like • One choice is better than others in some situations but not in all • Implement it in the core-mechanics • Example: Race game: lizard, frog, mouse • Advantages remain slight than overwhelming • Course complex mixture of rock, swamp, grass • Partial freedom to select routes • Add some shadow costs • Careful adjustment will make the game balanced sayed@justetc.net Www.JustETC.net

14. Orthogonal Unit Differentiation • Each type of unit a player can control in a game • Should be orthogonally different from all others • Each unit unlike than the others in a different dimension • Not in the same dimension • Race: ford, dodge – speed – differ in only one dimension • Make the units differ in power at one aspect but offer different qualities with each unit • To offer a large variety of strategies • To make the choice more interesting • Every unit should have capabilities that others don’t have • Each unit plays a distinct role • Little point to offer weaker units only upgradable to more powerful unit sayed@justetc.net Www.JustETC.net

15. Orthogonal Unit Differentiation • The more diverse your challenges are • The easier to offer orthogonally different units • Racing games are not good places as all the players will face similar challenges • War games can easily offer orthogonal units • Such units also help to prevent dominant strategies • Define the victory condition in such a way • The player must use a variety of different units to win the game sayed@justetc.net Www.JustETC.net

16. Dominant Strategies in PvE Games • One action to surmount all challenges • Makes a dull game • Games usually offer more challenges than actions • With a smaller set of actions players can • Experiment with the actions to overcome the challenges • Fewer actions does introduce a potential problem • Powerful esp. • Actions that can overcome several different kinds of challenges • You risk to create exploits • Actions so powerful that the player may become unstoppable • No straight forward rule • But testing will help • Try to play with as many actions and combinations possible to defeat a challenge • Smaller actions offer testability • Be careful with power ups and special actions that gives the player more power than usual sayed@justetc.net Www.JustETC.net

17. Incorporating the Elements of Chance • Use chance sparingly • Chance affects only minority of actions • Balance the effect of chance as follows • Use chance in frequent challenges with small risks and rewards • Allow the player to choose actions to use the odds to his advantage • Allow the player to decide how much to risk sayed@justetc.net Www.JustETC.net

18. Making PvP Games Fair • Fairness in PvP Games • The rules give each player equal chance of winning • At the beginning of the game • The rules do not give advantages or disadvantages to players unequally • during the game in ways that they cannot influence or prevent • apart from the operation of chance sayed@justetc.net Www.JustETC.net

19. Balancing Games with Symmetry • Decide the game to be symmetric or asymmetric • At the beginning • All PvE games are asymmetric • Symmetric PvP games are easier to create • Whatever you do for one player • You do it for all players • Give similar resources and power in the beginning • Also same condition sayed@justetc.net Www.JustETC.net

20. Balancing Asymmetric Games • Fox and Geese Example • Testing all possible combinations • Be lengthy sayed@justetc.net Www.JustETC.net

21. Making PvE Games Fair • The game should offer the player challenges at a consistent maximum levels of difficulty • No sudden spikes • The player should not suddenly lose the game • Without warning • And through no fault of his own • Learn by dying • The immortal • Give warning of danger • A stalemate should not occur • A condition from where both win or lose is impossible • The game should not ask for critical decision without informing the player with all information • Monty on the run • All the factual knowledge required to win the game should be contained within the game • The game should not require the player to meet challenges not normally presented in the game’s genre • Puzzle in Simulation Game sayed@justetc.net Www.JustETC.net

22. Managing Difficulty • Flow State • Ability balances with the difficulty • Peak Productivity • Too Much Challenging • Causes anxiety • Too Easy • Causes boredom • Absolute Difficulty • Perceived Difficulty • The perceived difficulty of a well balanced game should remain within a certain range • Should not have sudden spikes or dips sayed@justetc.net Www.JustETC.net

23. Other Balance Considerations • Balance Consideration • Avoiding Stagnation • Avoiding Trivialities • Avoiding Stagnation • The player is stuck – he does not know what to do • The game did not give him enough information to act • Hidden switch concept in first person shooter games • PvP: happens rarely • Stagnation can happen if the resource level is too low to act • PvP • Hidden boss enemy (after all enemies are destroyed) • Set a separate victory condition • Destroy the headquarter • Try to give some guide/hints at stagnation points • Gentle nudge sayed@justetc.net Www.JustETC.net

24. Avoiding Trivialities • Avoid uninteresting details • Example • Fuel Consumption, Where to store gold • Police Game sayed@justetc.net Www.JustETC.net

25. Design to Make Tuning Easy • Design to make tuning easy • Use generalized mechanics • Separate the code from data • Tune the mechanics for each entity separately • Fine tuning your game • Modify only one parameter at a time • Changing multiple parameter at once makes it difficult to understand which change affected the outcome • When modifying parameters, make big adjustments, not small ones • Double or half the value of a test parameter • Keep records • Focused on tester and testing • Be sure your programmers use pseudo-random numbers • To regenerate the issue sayed@justetc.net Www.JustETC.net

26. Managing Difficulty • Perceived Difficulty • Hard to compare difficulty level of different types of challenges • Even with the same type of challenges, it’s difficult to compare difficulty level • Complexity differs from person to person • Factors Outside the Control of the Designer • How much time the player has spent playing the game • Or faced similar challenges in similar games • How much native talent the player brings to the game • In multiplayer games, it’s the skills of the opponents that make the game hard or easy • Though if the game is fair not much effort to manage difficulty • Set difficulty of the challenges as posed by the environment sayed@justetc.net Www.JustETC.net

27. Types of Difficulty • It is the perceived difficulty that matters most • To design a challenge of your perceived difficulty • You should consider the following • Intrinsic skills required • The stress • Power provided • In-game experience • Absolute Difficulty • By using the absolute difficulty • you will be able to compare the difficulty level of different challenges sayed@justetc.net Www.JustETC.net

28. Types of Difficulty • Reactive Difficulty and Power Provided • In addition to measuring absolute difficulty • You need to measure • The power the player has been given • Relative difficulty • Difficulty of a challenge relative to the player’s power to meet the challenge • Perceived Difficulty and In-Game Experience • In-game experience: • The amount of time the player has spent to overcome any particular type of challenge • Level designers can keep this in mind for designing the difficulty level of games • Perceived difficulty = absolute difficulty – (power provided + in game experience) sayed@justetc.net Www.JustETC.net

29. Managing Difficulty • Creating a Difficulty Progression • The difficulty should increase with time • Increase absolute difficulty • Also increase power of the user • increase relative difficulty as well • Make the perceived difficulty also increasing • In a balanced game the perceived difficulty either should not change or will increase sayed@justetc.net Www.JustETC.net

30. Establishing Difficulty Modes • Games with multiple difficulty level • The perceived difficulty will not go above a certain point for a level • Action and Action Adventure Games • Designers normally • Give the enemies more health, • allow them to do more damage • Make them more numerous • Adjust the AI of the enemies sayed@justetc.net Www.JustETC.net

31. Dynamic Difficulty Establishment • Max Payne: First Person Shooter game: • Adjust enemy power according to player’s performance • Half-life • Check the state of the health of the avatar sayed@justetc.net Www.JustETC.net

32. Understanding Positive Feedback • Benefits of Positive Feedback • Positive feedback discourages stalemate • Positive feedback rewards success • Controlling Positive Feedback • Don’t provide too much power as a reward for success • Introduce negative feedback • Raise the absolute difficulty level of challenges as the player proceeds • Allow collusion against the leader • Define victory in terms unrelated to the feedback cycle • Use the effects of chance to reduce the size of the player’s rewards sayed@justetc.net Www.JustETC.net