1. Game balancing
Alex Graciov and Devon Gasparotto

2. Overview What is a Balanced Game? Dominant Strategies
Element of Chance
Making PvP Games Fair
Managing Difficulty
Understanding Positive Feedback
Other Balance Considerations

3. What is a Balanced Game? A Fair Game
Is not too easy nor too hard
Makes player skill the most important factor in determining success
Balance differs between PvP and PvE

4. Balanced PvE/PvP Characteristics
The Game Provides Meaningful Choices
The Role of Chance is Not so Great that Player Skills becomes Irrelevant
The Game Provides Meaningful Choices
- Game should allow player to choose from several strategies, and no strategy should be so much more effective than the others that there is no point in using a different one. This would be called a Dominant Strategy (poor balancing)
The Role of Chance is Not so Great that Player Skills Becomes Irrelevant:
a better player should be more successful than a poor one, not dependent on luck as much (child games may break this rule).

5. Well-Balanced PvP Charactersitics
The Players Perceive the Game to be Fair
Any Player who Falls Behind Early in the Game gets an Opportunity to Catch up
The Game Seldom or Never Results in a Stalemate, Particularly Among Players of Unequal Ability
Example: Chess
Left with King vs King
The Players Perceive the Game to be Fair:
fairness varies among different players
Any Player who Falls Behind Early in the Game gets a Reasonable Opportunity to Catch up Again Before the Game Ends:
if there is no opportunity for a player to catch up from early mistakes, it may be perceived as unfair. Also a game intended for a long time is won in a very short time by one player, may seem unbalanced where other players have no opportunity to test their skill.
The Game Seldom/Never Results in a Stalemate, Particularly Among Players of Unequal Ability:
stalemates are disappointing, because there is no victor. If this occurs frequently, violates rule that player skill should influence outcome.

6. Well-Balanced PvE Characteristics
The Player Perceives the Game to be Fair
Complicated due to lack of human players
The Game’s Level of Difficulty Must be Consistent

7. Dominant Strategies
Strategy is plan for playing a game, according to an approach that player believes will be successful
Dominant Strategy, is a strategy that reliably produces best outcome no matter what opponent does, thus eliminating all other options

8. Transitive Relationships Among Player Options
Is a relationship between 3 or more entities
If A is greater than B and B is greater than C then A is greater than C
Making A the Dominant Strategy
This imbalance can be fixed by imposing a Direct Cost on the entities

9. Direct Cost
Making A cost the most, and B cost more than C will eliminate the Dominant Strategy, forcing the player to choose appropriate strategy depending on the Cost.

10. Shadow Cost Costs that are hidden from the player
Smaller fuel tank on the Car, will cause more money wasted on fuel
In PvE this may seem unfair.

11. Intransitive Relationships
Rock Paper Scissors
If A beat B and B beats C, can’t assume A beats C

12. Orthogonal Unit Differentiation
Each type of unit should be orthogonally different from all others.
Each unit should display different qualities and possibilities.
A unique feature
In war games:
Some units may fly, travel on water, or ground
Each unit has it’s on purpose and unique ability

13. Design Rule
Differentiate All Your Units

14. Design Rule
Test Thoroughly to Eliminate Dominant Strategies

15. Incorporating the Element of Chance
Use Chance Sparingly
Use in Frequent Challenges with Small Risks and Rewards
Allow Player to Choose Actions to use Odds to their Advantage
Allow Player to Decide How Much to Risk
Use Chance Sparingly
– design game so chance affects only a minority of actions.
Allow Player to Choose Actions to use Odds to their Advantage
– skill in decision making helps to determine success. Chance may not be explicitly given, but an experienced player learns odds and will make better decisions. If player can’t learn odds, relies too much on chance.
Allow Player to Decide How Much to Risk
– gives more control over resources (reward skill). If there is no choice, the risk should not be too much. For example in a war game, chance affects the accuracy of shot, a unit will lose only a few life points on strike, and player can withdraw units at any time

16. Making PvP Games Fair PvP is fair when
Rules give each player equal chance of winning at start
Rules don’t allow advantages/disadvantages to player unequally during game in ways that they cannot influence or prevent outcome

17. Balancing Games with Symmetry
In PvP
All players play by the same rules and try to achieve same victory condition.
Both sides are identical (TF2, CS)

18. Balancing Asymmetric Games
Different players play by different rules
Must test mechanics for all combinations of types of competitors to ensure non-existence of dominant strategies (in-house testers, beta testers)
Developers
Testing Sucks!
Project Managers

19. Cheating AI and Secret Symmetry
Some games have AI that is not good enough to beat human players
This is solved be letting AI cheat (go out of bound of game rules) to make AI more interesting
This is allowed to a certain extent
As long as the player doesn’t notice or isn’t too obvious.

20. The Point Assignment System
Assign players identical quantities of resources or points to delegate to attributes at the beginning
Assigned points to offered units must be orthogonally related
Attributes should scale in the same way to avoid imbalance that may lead to dominant strategy

21. Starcraft – Perfect Example
Perfect example of asymmetrically balanced game
Each race offers flying, construction, infantry units
All units between races cost different and have different attributes, but all are balanced with each other.

22. Making PvE Games Fair
Game Offers Player Challenges with consistent difficulty increasing (No sudden spikes)
Player should not suddenly lose game without any warning and through fault of his own (learn by dying, Dark Souls)

23. Making PvE Games Fair Stalemate should not occur
Deadlock
Game shouldn’t ask player to make critical decisions without adequate information
All factual knowledge required to win should be contained within the game
Game should not require the player to meet challenges not normally presented in the game’s genre

24. Managing Difficulty

25. Factors Outside Designer’s Control
Previous Experience
Uncertain how long player has played similar games
Native Talent
Player’s natural talent to use during challenges
Multiplayer
Cannot control the player’s opponents’ skill.

26. Absolute Difficulty
Compare the amount of ISR (intrinsic skill required) to meet challenges and stress it imposes on a trivial challenge of the same type
Twice the difficulty for an enemy with twice the health

27. Relative Difficulty Power Provided Difficulty of a challenge relative
Measures player’s strength (player statistics)
Difficulty of a
challenge relative
to the player’s
provided power to
meet that
challenge.
Eg. Skyrim

28. Relative Difficulty
In Skyrim, the difficulty depends on the player’s Level, the higher it is, the more damage AI enemy inflicts on the player.
So leveling up just on Thief skills (lockpicking, sneaking etc.) and getting a level +80 in the process will not end well for you.
In persistent worlds, warn players against trying a mission that is too difficult

29. Perceived Difficulty & In-Game Experience
Player learn to handle user interface and mechanics more efficiently as they play
The difficulty the player actually senses
The type we are most concerned with
Perceived Difficulty = Relative Difficulty – Player’s experience
where
Relative Difficulty = Absolute Difficulty – Power Provided
The formula doesn’t use quantified values, but can certainly be converted to use.

30. Creating Difficulty Progression
Consider
Player’s in-game Experience
Increasing Power
Perceived Difficulty should not change for young children/infrequent gamers

31. Evolving the Player Increase Absolute Difficulty of challenges
Increase Power available
Ensure player doesn’t gain experience, such that challenges get easier

32. Design Rule
Don not jump difficulty from level to level

33. Difficulty Modes Easy, Medium, Hard
They should not overlap with each other
Accounts for native talent and previous experience
Potentially increase market

34. Design Rule
Easy Mode Means Easy

35. Dynamic Difficulty Adjustment
Detect player skill and adapt experience
Mechanisms:
Performance-Evaluation
Adjustment Mechanism
Approaches:
Adjust enemies and other characteristics based on performance

36. Dynamic Difficulty Adjustment
Approaches:
Rubber banding in racing
Training Tutorials

37. Dynamic Difficulty Adjustment
Approaches:
Detect when player is dying frequently and offer bonuses

38. Positive Feedback
Player achievements changes game to make subsequent achievements easier

39. Positive Feedback Examples:
Give Advantage to Leader – easier to maintain lead
Discourage Stalemate
Reward Success, provide Reward in a Useful form

40. Control Positive Feedback
Should not occur quickly – prevents players from catching up
Ways to control:
Don’t Provide too much power as reward
Restrict player’s power
Costs and Benefits with player achievements

41. Control Positive Feedback
Ways to Control:
Raise Absolute Difficulty as player proceeds
Collaborate against Leader

42. Control Positive Feedback
Ways to Control:
Chance to reduce size of rewards
Define Victory in terms unrelated to feedback cycle (i.e. distractions)

43. Positive Feedback Applied

44. Avoiding Stagnation Stagnation: player doesn’t know what to do next
Lack of info to proceed
Help Player:
Hide clues on how to proceed (in plain sight)
Give guidance to wandering
player

45. Avoid Trivialities Let Computer handle
Can use trivialities, but should be Infrequent

46. Make Tuning Easy Entity has its own mechanics
Must be tuned separately to prevent imbalance
Tweaking should not unpredictably throw off balance
Separate Code from Data