Thursday, October 29, 2009

On Balance, Part 2: Ten Key Tips for Balancing

On Monday, I wrote about the fundamentals of balance. Here’s the second and final part of that discussion.

Here are ten important take-aways from Sirlin’s series on balance, but with an MMO bent. These tips cover a wide range, from ways to find imbalance to ways to quantify and fix those imbalances. I added specific MMO-related applications of some of Sirlin’s points about balancing fighting games.

Finding Imbalance through Tier Lists

  • Ask players to organize classes, character types, and abilities within each class into five tiers based on their power or usefulness in different scenarios. The highest tier should be “God”-level—these are dominant strategies—and the lowest tier should be trash-level—these are strictly dominated strategies. You want to clear out those two extremes and ensure that the other tiers are as close together as possible.
  • Tier lists can be applied to classes or abilities in MMOs, but with a caveat. Characters in typical fighting games are mutually exclusive in the context of play—a player can not be more than one character at once. But in an MMO, a character can have multiple abilities at once and those abilities can be at multiple power levels.
  • In a class-based game, it’s easy to apply the tiering system: for each role, tier the classes in their effectiveness. It’s not a disaster if a class is God-tier in one role, as long as it isn’t God-tier in too many, making it basically a dominant strategy to play that class (ala Channellers in Shadowbane). You can use tiering to roughly balance the utility of each class in different situations. It’s a good idea to make the design intentions of classes available to the player so that they don’t make a terrible decision when they choose a class that gimps them at doing what they love.

Avoid Imbalance through Preventative Design

  • Imbalances are avoided by the use of counters. Sometimes these counters are passive: Elemental damage is countered by elemental resistance; physical damage is countered by dodging, blocking, and armor. Sometimes these counters are active, like using a shield bash to interrupt a healer casting a life-saving heal spell.
  • Design counters and counters to counters. But don’t turn your game into rock-paper-scissors.  Iterative deletion of dominated strategies can be used to determine where bedrock is hit. Sometimes counters can be generally weak, but they can exist just to counterbalance a possibly exploitable mechanic.
  • Don’t become fixated on balancing at a micro-level. In a class-based game, you’re balancing class against class, not ability A against ability B. Keep this in mind—sometimes combos of a class’ abilities can make it overpowered and you’d miss that if you were focusing on micro-level ability balance.

Balance Towards Fun

  • Abilities have to be powerful. Balancing games isn’t about lining numbers up so that they sum to zero, it’s about making the game as fun as possible for as long as possible.
  • Maximize the time where both sides have a fighting chance. Always give each side a reason to fight further—there should always be something to lose worth protecting and something to gain worth taking. Be careful of runaway negative and positive feedback loops.
  • Always pull the bottom up to meet the top. This can be difficult in MMOs, but you should work very hard to avoid nerfing classes or abilities. It’s better to have a gap filled a little too much than to leave a void.
  • There should be gamist reasons why every mechanic is present in the game. There should be simulationist reasons why mechanics work as they do. The challenge is to pick the mechanics that are balanced for simulationist reasons—actually real-world systems that balance one another aren’t easy to find.


pxib said...

"Always give each side a reason to fight further—there should always be something to lose worth protecting and something to gain worth taking."

This is absolutely true, but maximizing fight time can be brutal, and feedback loops can work to your advantage. Winning players are always happy to have extra time to gloat, but once players think they're going to lose, many just want the game to be over. Team Fortress 2, for example, implemented a number of dynamics that let a winning team win quickly once they've established dominance.

Unless players are allowed to abandon a losing battle (ideally to a different, winnable one), much effort will have to go into keeping them ignorant of who's winning.

Brian 'Psychochild' Green said...

A few thoughts.

1. Counters are vital because they add a bit of unpredictability to the mix. Avoid one power being the "final say", though, otherwise that often becomes a dominant strategy. Also make sure that characters who are countered in one area have access to alternatives; if a silenced caster cannot do anything, silencing abilities will be seen as too powerful.

2. Remember that different balances exist for different types of gameplay. A class balanced for solo play vs. group vs. raid vs. PvP might be completely different. Take a tank class, they might suck at solo play and PvP, but be invaluable for group and raid content. How do you balance that against other classes?

3. Balance, particularly in PvP, depends on fashion. A class with abilities that are great against a single enemy class might become more powerful if that enemy class becomes more dominant in PvP. For example, the ability to silence a caster is going to be potent if casters dominate PvP, and less useful if melee characters are the flavor of the month. The ability doesn't have to change at all to change in effectiveness. This is also a weakness in "rock-paper-scissors" type balance. If everyone plays paper and there are no scissors, rocks are going to feel put upon twice: nobody for them to beat up and nobody to keep their natural enemy in check.

Personally, I've never found balancing to be as hard as people complain. I think the biggest problem is when a developer overreacts to a problem and tries to do too many changes to fix a perceived imbalance.