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