Game balancing Alex Graciov and Devon Gasparotto

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

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

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).

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.

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

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

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

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.

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.

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

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

Design Rule Differentiate All Your Units

Design Rule Test Thoroughly to Eliminate Dominant Strategies

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

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

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)

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

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.

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

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.

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)

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

Managing Difficulty

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.

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

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

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

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.

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

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

Design Rule Don not jump difficulty from level to level

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

Design Rule Easy Mode Means Easy

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

Dynamic Difficulty Adjustment Approaches: Rubber banding in racing Training Tutorials

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

Positive Feedback Player achievements changes game to make subsequent achievements easier

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

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

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

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

Positive Feedback Applied

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

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

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