The Character-Player Gap

In tabletop games, it’s important to maintain the gap between the player and the player’s character. These games hinge on the players roleplaying—the conflict resolution mechanisms are a big aid in the process. The quality of a game of D&D often depends largely on if the players can maintain a separation between themselves and their characters. When the players roleplay their characters effectively and don’t metagame too heavily, suspension of disbelief can take hold and lead to intense immersion. If the gap closes between the player and character, the game becomes a poor simulation with little soul.

MMO design, though it finds its roots in tabletop RPGs, cannot work off the assumption that there is a gap between the player and character. Social competition and cooperation force the gap shut.

How the Gap Closed

In order to compete most effectively against other players (i.e. take the path of least resistance at every possible point and maximize gain) the character is discarded. Roleplaying is significantly less efficient than playing as yourself, so a player motivated by competition will not bother doing it.

To cooperate most effectively in games, players use tools like voice chat that will erode the sense of talking to the character. The player’s interaction with the game world is no longer tightly bottlnecked through the game, it spreads out onto forums, vent channels, IRC, and IM clients. It becomes significantly more difficult to maintain a character-player gap under this diversity of contact—and most of this contact is necessary to cooperate most effectively.

If there is a not a social contract based around roleplaying, people will not roleplay. One or two people failing to roleplaying consistently leads to exponential numbers of players thinking it’s OK not to roleplay. So games cannot expect roleplay where there are a significant number of new players who are not familiar with the concept.

What Does It Mean?

Design games that don’t rely on their being any separation between player and character. Don’t limit the player’s ability to talk to other players because they are not on a certain character. At its most superficial level, persist guilds and friends lists across an entire account (perhaps on a server-per-server basis).

We can only safely assume that a player is roleplaying when he’s interacting with NPCs. MMOs should have a wider variety of NPC interaction choices. NPCs need to have lives that mean something to players—this alone will lead to a significant change in the meaningfulness of an MMO’s world.

The closing of the character-player gap doesn’t necessitate gutting systems of all immersion and stripping them down to their most addictive mechanics. The player character primarily needs more means of effecting the world that are affected by the character and not the player. We simply cannot rely on the player to roleplay in any form. We must fashion gameplay around this fact, not, as WoW and its descendants have done, in spite of it.

(When I present the design for the MMO I’d like to make, you’ll see more clearly how I intend to do what I say here.)

The Abstraction of Character

Perhaps my post about the abstraction of character progress was a bit premature. I defined the progress of characters without defining characters. This post will fill that gap. I aim to present vocabulary and set of patterns of defining and analyzing character abstractions as they exist in RPGs. (This may also be applicable to other genres, as well.)

A pragmatic view of a character in a game world would consist of two facets:

• State: A physical manifestation of the character in the game world, this implies a description of the character.
• Behaviors: A set of abilities that the character uses to interact with the game world.

More simply stated: a character’s meaning consists of what it is and what it can do. Characters allow interesting gameplay because their state affects what they can do and what they can do can affect their state.

State

What is the character?

Typically we describe a character (in terms of game mechanics) using a set of attributes. Attributes are the “ability scores” that are ubiquitous in modern RPGs: strength, dexterity, agility, constitution, intelligence, leadership, wisdom, charsima, etc.. Attributes only exist because they effect the abilities of a character; they represent the capacities of the physical being of the character.

Attributes are either intrinsic or derived. Intrinsic attributes belong to the character’s very being—you can’t break down their capacities further than intrinsic attributes. Intrinsic attributes are the individual variables in the various equations that dictate the effectiveness of abilities. Derived attributes are constructed through the mathematical combination of intrinsic attributes.

Although it doesn’t matter in most MMORPGs, attributes can be used in either their base or modified form. The base form is simply the attribute’s value when no novel effects apply to the character. The modified form arises when some effect happens to the character that changes the attribute. Permanent attribute damage or permanent attribute growth, as happens when a character levels can alter the base attribute value.

Behaviors and Effects

What can the character do?

Usually characters are quite limited in their actions. They can move about the world at varying speeds, but can only touch the world through killing creatures or combining ingredients to make items. On a smaller scale, characters are limited to a certain set of relevant abilities in each kind of activity they can undertake. In crafting, this is usually restricted to each type of item they can craft—an ability is to execute a recipe. In combat, a character has a number of abilities that center on changing the attributes of itself or other characters involved in the combat. The effectiveness of all of these abilities is dictated by individual abilities’ mechanics and the attributes of the character executing the ability.

A Schematic for Describing RPG Character Systems

Here’s my attempt to define a generic way to describe any RPG system. This is not set in stone: it may be incomplete, so please let me know if you can think of systems that this does not cover or anything else I’ve omitted. I will edit this schematic based on input from comments.

Define a set of attributes. Each attribute has

• A name.
• If the attribute has mutually exclusive values (like eye color).
• If the attribute can have multiple values simultaneously (like heritage).
• If the attribute is to be represented as a number:
• Its resolution. (The smallest increment possible that the attribute will recognize or allow.)
• (Optional) Its range. (The smallest and highest numbers possible.)

Define a set of abilities such that each ability has

• A name.
• A list of effects, such that each effect has
• (Optional) a name.
• A magnitude, either as a flat number or as an equation in n-dimensions that may refer to any set of attributes or external conditions. (The amount of damage dealt, hp healed, strength regained, etc. may rely on character level, strength, the color of the character’s hair, the phase of the moon, etc.)
• Either:
• An attribute effected.
• Something created that has its own unique state, which may consist of a different attribute system entirely and different abilities that should be defined on their own terms.
• A duration. (Instantaneous, permanent, or expressed in some unit of time.)
• A set of targeting rules. What will this effect affect?
• A set of triggering conditions. The effect could happen immediately or be reliant on some other condition, such as a certain amount of an attribute, the character’s knowledge of non-euclidian geometry, etc..
• A set of keywords that describe the effect. (A fireball would have the “fire” and “area of effect” keywords, for instance. These exist to allow effects to be modified by one another.
• A list of costs, such that each cost has:
• A duration. (If an effect needs to be sustained and the cost isn’t paid up front or if, for instance, the character debuffs itself in exchange for some other benefit.)
• A magnitude, either as a flat number or as an equation in n-dimensions that may refer to any set of attributes or external conditions.
• An attribute or object in which the cost is paid.
• A list of triggers that could cause the cost to be paid, modified, or diminished.

Taste and Appreciation

Music is important to me. I’ve been playing drums for twelve years, though I only developed a significant interest in music 8 years ago (during my high school years).

It’s easy to settle into a groove and only listen to a certain kind of music that you find comfortable. Most people have their taste set in stone from when they were children. They listen to the music that they are comfortable with. Often this means listening to the music that they’ve heard the most—whether it be through the radio or through their parents—and occasionally adjusting to whatever music happens to be popular (i.e. what music is currently being listened to the most).

In gaming, it’s even easier to settle into the comfortable at the expense of everything else. Games are more expensive, less available, and take longer for developers to make. A $12 album can be made in 6 months. A great game takes upwards of a year and will cost $50 to $65. In this climate, it’s more beneficial for game industry participants to be risk averse and simply produce games that are slight incremental improvements over the last popular game—or even games that are direct clones of whatever is popular. When a player learns how to play a game and finds he likes it, he’ll certainly be interested in playing more of the same. It’s comfortable, just like the pop music from when you were a child. Reliving it makes you feel nostalgic. It’s easy for people to fall into a pattern here and accept what is given and look no further.

The first step towards developing taste is being able to discern one thing from another. This involves paying attention. The majority of those who play games or listen to music do not pay attention to it. The game or song plays its role or fills a gap and for that, the player or listener is grateful. Almost any song or game can come to fill this gap, though. Discerning means that you are sensitive to how different games or songs fill that gap. When you discern, you can pick out things that you like more or less and identify why that is, even if it’s only because you understand that you like certain facets of the experience and dislike others.

Once you learn to discern, you gain interest. You have a vague notion of what you like, so you try to seek out more things that you’ll like. Through this process, you expand your knowledge of the area in question. Someone who likes strategy games might expand backwards in time and play classics like the original Command & Conquer and Total Annihilation. Through indulging your interests, you can further discern. Here your taste takes shape.

Eventually you have learned enough that no longer are your discernments of a “I feel X” nature, they become intellectualized. You gain an understanding of why a song is arranged a certain way. You start picking up on what makes a good level in a shooter. Now you don’t just know what you like by matching up an arbitrary list of preferences against some object you’re listening to or playing, you can make meaningful objective statements about what most people are think are subjective topics. You have gained an understanding of the topic, and through this understanding you’re capable of finding just the right kind of game or song for this point in your life.

At this evolved stage, you can see your own preferences changing and you may even be able to put your finger on why. You arrive at some fundamental ideas about why you love music or gaming. You dig deep and find games and songs that you absolutely love. Your life is enriched by the experience, and you wish everyone could enjoy the object of your evolved taste just as well as you can.

Music has taught me how to expand and develop my tastes. I’ve learned much about how to find new material and give it an honest chance. I’ve learned how to find what should be appreciated, and then how to appreciate and enjoy it. One band in particular that widened my musical horizons through hard listening and close attention is Venetian Snares. VS makes some very intense drill & bass music. It’s hard to listen to at times, it can border on complete chaos. The patterns are complex and the sounds used are unorthodox. It took me many listens to grasp what was going on in this music and gain an appreciation for it. Through learning how to listen to VS I felt I had developed my ability to learn how to enjoy new things by coming at them from different angles.

Through stepping beyond what is comfortable and becoming immersed in the strange and different, we can start small-scale personal transformations that can lead to a significant increase in the amount of enjoyment we derive from life. Developing taste is one of the most important processes a human being can go through. I hope you have experienced what I discuss here. If you haven’t, please go out into the world and find new material that interests you, be it in poetry, music, prose, gaming, horseback riding, or breeding dogs. Don’t just be a consumer, develop an acute taste and gain a deep understanding of a topic—it’ll enrich your life more than I can describe to you even given another ten thousand words.

10+ Hour AI War Campaign Complete

Any fan of strategy games should play through at least one campaign of AI War in their lifetime. James Murff puts it well in his review (which has recently been featured on the front page of AI War’s website):

AI War is, quite simply, the best experience you could have with co-op or single-player real-time strategy in this or any year. It combines grand strategy with emergent AI to form an excellent game perfect for parties and multiplayer. It is easily worth double the price that the developer is selling it at, and anyone with any affinity or taste for strategy games should not miss it. It may be daunting at first, but an excellent tutorial and amazing gameplay mechanics alleviate this into a game that almost anyone can - and should - play.

- James Murff, Big Download

A “game” of AI War can last anywhere between 6 and 36 hours; that’s why it’s called a campaign. I successfully finished my first AI War game yesterday, so now I feel somewhat qualified to talk about the game here.

After spending approximately 20 total hours playing co-op games of AI War, I can safely say it’s the most fun out of any co-op strategy game I’ve played. And it’s only $20. I’ve played titles that cost $50 that have half the playability and a quarter the fun.

I will provide a summary of AI War’s mechanics below, with analysis coming within the next week or two. The design of AI War is relatively unique and deserves closer study.

An Introduction to AI War

You and, perhaps, one or more friends fight for control of a galaxy against two AI opponents that have superior equipment, superior numbers, and a significant head start.

AI War is asymmetric: you and the AI don’t play by the same rules. The AI has already inhabited your galaxy, and has built thousands of ships, turrets, and warp gates with which it can bring in many more ships. The AI is only limited by how much of a threat it perceives you and your friends to be. This threat level is measured by an AI Progress number visible at all times at the top of your screen while you play. This number increases as time passes and as you defeat the AI's’ strongholds. The higher AI Progress gets, the stronger the AIs become. They’ll throw more ships at you, they’ll throw better ships at you, and they’ll build up defenses faster on adjacent planets.

Scope

The battle is waged across 40 to 120 planets connected by wormholes. Each planet has its own sector of space in which you’ll fight massive battles with thousands of ships and  build various defenses and buildings.

You’ll build tens of thousands of ships and hundreds of turrets and buildings in each campaign. The game allows you to loop build queues—you’ll be making good use of this feature. Ships are expendable and you will suffer losses. You’re fighting an uphill battle.

Most of strategy is on the macro and grand strategic layers. You’ll be shuttling ships between your planets to bolster defenses and prepare your own attacks and you’ll be commanding a thousand ships on a planet as they battle against AI forces. You’ll manage your resource income by activating and deactivating manufactories, and you’ll be turning different ships and builds on and off as your energy needs change. There are a wide variety of economic and military activities to attend to. Logistics is important, but doesn’t bog the game down.There is very little micro required, but some babysitting is occasionally necessary to ensure attack forces are moving on an efficient path from enemy stronghold to enemy stronghold.

Resources

There are four main resources: minerals, crystal, knowledge, and energy.

Minerals and Crystal are your typical RTS resources. You build harvesters on resource nodes to reap a constant stream of resources. You can build manufactories to convert one into another with some loss (right now it’s 12 of one convert into 8 of the other, per second).

Knowledge is a much rarer resource. Each planet has 2,000 knowledge on it that can be harvested by parking a science lab ship on the planet. Once the 2,000 knowledge is exhausted, it does not regenerate. Knowledge is one motivator for conquering neighboring planets. Knowledge is spent on buying technological advances. There are three tiers of standard ships that you can buy access to at a science lab (tier I is accessible at game start, tiers II and III are unlockable at the science lab). You’re going to need access to higher tier ships because the enemy will have more advanced ships as you push further into the galaxy. Ship caps (as I will discuss later) become a bit of an issue as the game progresses, and unlocking new ships adds to your cap space.

Energy runs all of your ships and buildings. Generators convert minerals and crystal into energy. There are three energy generators, from tier one to three. Energy production steps up significantly (along with build time) from one tier to the next. Building more than one of each on a planet will lead to decreased energy output from subsequent generators on the planet. This is another mechanic that forces you to conquer more planets. Energy will become scarce as you build up forces in the early game.

Planets

The space around planets acts as the stage on which your struggle against the AI will play out.

AI War is not a game where the optimal strategy is to take everything and steamroll your opponent. AI Progress will build up too fast if you take every planet. You’ll waste too many resources trying to take unimportant planets if you try to take everything. Wasting resources in AI War is punished severely by AIs attacking in force from multiple planets at once. AI War rewards fighting efficiently more than it awards total conquest. If you only take what you need, you will have a significantly improved chance of victory.

Each planet has a certain number of crystal and metal nodes. Some planets have special capturable enemy buildings and ships. Capturing advanced researching facilities grants you access to new ships; capturing advanced factories allows you to build tier IV ships (the highest tier ships a human can build); there are also missile silos and starship constructors that you can capture, but you can build them yourself without having captured them. Occasionally you’ll find data centers which, when destroyed, will reduce the AI Progress.

Planets are captured by destroying the enemy orbital command station and building a colony ship with which you construct your own station on the planet. Once you’ve built your own orbital command station, any capturables are transferred to you. If you haven’t taken out all enemy ships in the sector, you may find the capturables quickly destroyed by retreating enemy forces.

The goal of the game is to first survive, then to destroy the AIs’ home planet command stations. Once you’ve destroyed both home planet command stations, you win the game.

I’ll post analysis of the mechanics and dynamics of AI War within the next couple of weeks. Check the game out—if you like grand strategy, you’ll definitely get your money’s worth and much more.

Use-based Skill Gain, Revisited

My post on the character progression has informed my previous analysis on use-based skill gain. Using the tools I provided in that article, I’d like to re-examine use-based skill gain in more detail and draw some distinctions that I missed last week.

Ryzom vs. Darkfall

We are only concerned with systems that grant XP based on the use of specific abilities within a skill-based system. These systems are called “use-based” because the amount of XP you get towards an ability or ability group depends on how much that ability or an ability within that ability group is performed by the character.

Ryzom and Darkfall illustrate two distinct approaches to use-based skill gain. Here’s how their systems answer the three “scope of experience” questions:

• What will grant experience?
• Darkfall: Performing any action to completion.
• Ryzom: Completing a quest or killing an enemy.
• What will an experience point apply to?
• Darkfall: The ability group to which the action belongs that granted it.
• Ryzom: XP is distributed proportionally to ability groups depending on the abilities used to kill a monster. XP is scaled based on the difference between ability group level and enemy level.
• What can an experience point be spent on?
• Darkfall: Only on increasing the level of the skill or skill group to which the experience point applies.
• Ryzom: XP in an ability group goes towards leveling that ability group. Once the group is leveled, XP is converted into points used to buy new abilities and effects.

Runaway Positive Feedback

Notice how narrow and direct Darkfall’s system is. You get XP that is allocated to what you just did. You can’t specialize in any way beyond what you’ve done because of the narrowness of experience’s scope. If you want to perform well (before you’ve capped all your abilities—the lack of cap really kills specialization at growth’s end), you are stuck using the abilities that you’ve used most. So if you are pushing yourself by trying the most challenging content you have a chance at completing, you are stuck using the same set of abilities to the exclusion of almost all else. The positive feedback loop created in this way does not meet its end until you reach the ability cap. Then, and only then, does an optimal build begin bringing its other abilities up.

The pendulum swings between the necessity of complete specialization during character growth to the complete lack of specialization at growth’s end. I see this as the worst of both worlds. To play optimally, you’re trapped into using only what you’ve spent the most time using—until you’ve maxed everything out, at which point it doesn’t matter.

By broadening what XP can be spent on, a system allows specialization beyond exactly what the character is using. Ryzom’s system benefits significantly from letting players choose what their experience will improve within an ability group, instead of forcing the growth to occur in specific points. The positive feedback loop of growth in a certain area spurring further growth does not disappear, but it is significantly moderated.

Exploitation 

A system is more exploitable if the rewarded action is one swing of a sword. If the completed action is broader—like, say, killing an enemy in Ryzom’s system—then the problem largely goes away. Ryzom’s system proportions XP in a use-based fashion, but doesn’t focus all growth only on counting ability use.

The optimal strategy for becoming a master swordsman should not be:

• Find a friend who can debuff attack power and buff defense.
• Have him debuff your attack power.
• Have him buff your defense.
• Find a mob that has a lot of health.
• Debuff the mob’s attack power.
• Buff the mob’s defense.
• Swing at the mob a million time until it dies.

If that is feasibly the most effective way to gain skill levels, the system is broken. It’s trivially easy to level up that skill. In Ryzom’s system, you can’t gain XP beyond some fixed cap for a given monster, regardless of how many times you swing your sword at it. It’s clearly easier to exploit a use-centric use-based system than it is to exploit a system that rewards only broader accomplishments, like killing an enemy.

Limited Reward Potential

Darkfall has such as strict conception of use that characters cannot be rewarded for any activity above the use of an ability. Why should a system be so restrictive? It cuts out much of the benefit in the experience point abstraction. Ryzom reaps the rewards of using an experience point system while still maintaining the customizability and flavor of a skill-based advancement system.

Use-centric Advancement Systems are Inferior

It’s important that we draw the distinction between use-centric systems, like Darkfall, and other use-based systems. Use-based systems filter XP towards limited ability groups based on what abilities were performed to cause the XP gain. Darkfall’s system represents a pure version of this where use is the center of advancement: all character progress is based directly on use and little else. Systems work better when, like Ryzom’s, use has a more abstract incorporation into how character growth happens.

Your Job is to Make Tasty Sandwiches!

I walked into a Subway sandwich store for the first time earlier today. After ordering, I was confronted by a lot of options that weren’t presented in an efficient way. There were approximately four steps where I had to make some choice as to what to put on my sandwich—four distinct phases where different ingredients were either added or withheld from the sandwich.

When the sandwich was completed, it has a total of 4 ingredients in it (bread included).

I ordered a sandwich that had a distinctive name that suggested almost every ingredient that would be present. “Sweet onion chicken teriyaki” leads me to expect the sandwich has onions, teriyaki sauce, and chicken on it, probably with lettuce thrown in because that’s how sandwiches are usually made. Instead, after ordering the sandwich, I was confronted with four different decisions, each with more than four options. It was not clear at all what would go on this sandwich or what should. Why is that? Because I am not a professional chef. I don’t go into the store expecting to be saddled with making myself a good sandwich. I went to the store so that I could buy a good sandwich that they had thoughtfully designed and put together.

This is a great metaphor for a significant problem application designers face: giving the user as few decisions as possible while allowing them to effectively and easily use the application to accomplish their goals. Subway failed at this basic design problem by saddling me with far too many choices, almost invalidating its primary reason for existing (to sell me tasty sandwiches as easily and quickly as possible so as to make a profit).

Aion makes an innocent but devastating mistake in an effort to simply make a tasty sandwich. They’ve streamlined their game into a candy-coated, artificially enhanced stream of purpose-built monotony. Dungeons and Dragons 4th Edition falls into this trap as well.

When you log into Aion, you enter a world that is clearly made so that you can run around and effectively kill monsters. Everything’s arranged nicely for your viewing and killing pleasure. The ducks are lined up and a well-maintained rifle is put in your hand for an enjoyable afternoon of shooting—but the ducks are wooden and the rifle doesn’t shoot anything, a wooden duck flips backwards whenever you fire. The gameplay is directed; it’s so directed that, after 10 hours, it felt completely empty to me. My path through the game was perfectly clear. It was so well lit and nicely paved that I felt that I might try a different, dustier, less-traveled path. But there was no other path.

Dungeons and Dragons 4th Edition (4e from here on) streamlined the hell out of the tabletop roleplaying—or, perhaps more aptly, rollplaying—experience. Its predecessor, 3.5e, was asymmetric, arcane, and had a serious case of power creep. Wizards of the Coast apparently had enough of that and decided to finely tune the 4e rules to cut off all those rough edges and remove the arcane and less-trodden paths, to simplify the complex, and to run out of town all the rules but those that governed situations that could be vaguely described as combat. Suddenly the sprawling 3.5e is replaced by a very consistent, smooth 4e that has all the corners neatly rounded and all the danger areas surround in safety fences. 4e is a game system that is very obviously a game—it has clear boundaries that become quite obvious when you try to run a 4e campaign. All those fun utility items that abounded in 3.5e are gone. The unique and flavorful mechanics of each class are replaced by abilities that are minimal variations on a consistent framework. The abilities and, by extension, the classes, feel like repackaged and rebranded copies of the same few ideas.

Streamlining games can solve mechanics problems, but it ultimately rips the soul out of a game. When all of the interesting detail is stripped and all the excitement is paved over, it doesn’t matter if the game is perfectly balanced: it simply will not have enough flavor to be fun. You might leave the game feeling like it was well-balanced and complete, but you won’t find yourself excited.

The Abstraction of Character Progress

The first post I made here on That’s a Terrible Idea documented the four core design elements of MMORPGs: conflict resolution, goal generation, power growth, and player interaction. In my 10 Points, I point out ways that each of these core elements will change in the MMO Revolution. We haven’t discussed these elements in much depth (aside from a couple posts regarding accountability systems to facilitate dynamic world player interaction). The recent discussion of use-based skill gain has caused me to return to these basic mechanics and spend some time analyzing the fundamentals of character growth mechanics.

RPGs are defined by the fact that as characters accomplish tasks in the game world they grow—and this growth is independent of the player gaining skill. There are two fundamental mechanics to character growth that all RPGs possess:

1. Character advancement is granulized into some form of experience points. Experience points might be renamed, or be hidden, but they are always there in some form (even in Darkfall).
2. Based on how many experience points characters have, characters unlock abilities and bonuses.

It’s obvious to someone who plays these games, but it’s crucial that this basis is understood. Now, we can get to the meat of the skill-based vs. level-based advancement debate: How continuous (or discrete) should advancement in RPGs be?

Power Curves

The gamut runs between the most discrete system, one where there is one transition in power level that happens instantaneously, to the most continuous system, one where every single action performed increases the success chance of the next action performed.

Discrete systems have clearly defined jumps in character power. These jumps are monolithic and all-or-nothing.

Continuous systems have a smooth gradient of power growth. There are many small jumps and these jumps are specific to certain facets of the character.

Class-centric level-based approaches are the most familiar and common RPG character growth schemes. This discrete scheme leads to a power curve that looks like this:

The step-like curve is the result of discrete changes in power linked to gaining character levels. It takes longer to level the stronger the character is, and there is less of an increase in power at each level. Max level is the only exception, where the character gets her endgame abilities which are usually a bit of a jump in marginal power gain from her abilities gained at max level minus one.

When advancement is localized to specific abilities, as in skill-based systems, a roughly continuous power gain results.

As the character interacts with the world, she continually gains ability in various areas, leading to a smooth power gain that marginally decays as time increases. In skill-based systems, the character is comparatively always gaining power.

The Results of Growth

Without some resultant effect on a character’s capability, growth is nothing more than a symbol (usually a number) of the character’s efforts in the game. In RPGs, growth is a primary positive feedback loop that rewards characters who accomplish important or impressive feats. At some point, growth grants a character abilities and effects.

Abilities are the actions the character can achieve in the game world, some of which are

• Casting a spell
• Performing a powerful melee attack
• Making a bandage
• Shooting a bow
• Poisoning a weapon

Abilities are often arranged into ability groups—character classes are series of ability groups, one per level. Talent trees in World of Warcraft are ability groups. Ability groups allow access to be granted or denied to different sets of abilities. These grouping can be logical or mechanical. Logical groupings exist to allow the player to better conceptualize how abilities relate to one another, whereas mechanical groupings are higher-abstraction-level units of character capability that can be affected by different game mechanics. Tradeskills are a logical grouping of abilities, whereas fire magic is a mechanical grouping.

Effects are changes in the character’s stats, a passive bonus to that character’s capability. An increase in strength or vitality, for instance, is an effect.

The Scope of Experience

Experience points are the most common name for a resource that symbolizes growth. Growth resources alone account for several crucial design decisions:

• What will grant experience points?
• What will an experience point apply to?
• What can an experience point be spent on?

Classical class-based systems assume that experience is assigned (or applied) to the whole character and that experience points can only be spent on gaining character levels. The character is rewarded with experience for every encounter she solves and every bit of the story that she completes. This experience applies to her whole character and can be spent on a new character level when the quantity of experience crosses certain thresholds. Every facet of the character advances at once.

Skill-based systems have XP that applies in a smaller scope. XP may apply only to the ability that led to the XP gain, as in Darkfall. XP may be gained by the character as a whole, but only be applied to one ability at once, as in Asheron’s Call. Their may be multiple growth resources that are spent in different ways, as is the case in Final Fantasy Tactics. The hybridization of skill- and class-based systems can yield a lot of variety, though most of the possible systems, as Psychochild would say, suck.

When XP applies to less of the character and can be spent on smaller units of growth, character advancement becomes more continuous.

A Schematic for Character Growth

Based on the discussion above, we can construct a schematic that describes all character growth systems. By defining the following, we can accurately describe the character growth mechanics in a game:

• A set of abilities, their prerequisites, and their growth costs.
• A set of effects, their prerequisites, and their growth costs.
• A set of growth resources.
• A set of completed actions that grant growth resources and how much of each resource they grant.

All character advancement systems are a combination of a these few basic concepts. Understanding them as such can help us evaluate game mechanics without becoming caught in the rhetorical traps and false distinctions that doom so many discussions to religious warfare and unproductive pontification.