Have you ever heard of heterosis?

Also known as "hybrid vigor," this is the process by which the offspring of two different strains of a species sometimes express the best parts of both parent strains. Such offspring often demonstrate a survival advantage over purebred offspring.

I've been wondering lately whether something like this might be applicable to single-player and massively multiplayer online games. Suppose we were to say that the "best parts" of these two strains of computer games (in particular, computer-based RPGs) are the player-centric focus of single-player games, and the persistence of massively multiplayer online worlds.

What if a game could be designed to have the size and depth and persistence of a MMORPG, and the character-focused story and gameplay reward structure of a single-player CRPG? Would such a game inherit the recessive flaws of its parents and be stillborn? Or could it be the first game to emerge with the vigor to successfully exploit an unexplored niche in the computer game environment?

I think there are reasons to believe the latter might be true. The rest of this article will explore some of those reasons from the perspectives of the players, developers, publishers and operators of such games.

The "Living World" Defined

Both single-player CRPGs and MMORPGs are obviously capable of commercial success. But both also have certain defects that are inherent to their content delivery model.

The typical play experience of today's single-player computer games is "played it, beat it, sold it." While some gamers may not mind this as the norm, it has important consequences for game developers and publishers, the most important of which is the need to extract as much money as possible from the consumer in one fell swoop. This depresses sales due to the perception of high cost, and increases the effect of piracy (since there's only one opportunity for a sale).

At the same time, developers and operators of massively multiplayer online games have the problem (arising from rarely-repeated interactions in relative anonymity) that some people are jerks and/or cheats, and only a few of these in a gameworld can spoil it for many others. This requires that the developers of an online gameworld add considerable amounts of special-case code solely to prevent players from griefing each other, and that operators of such games actively monitor them to detect cheating and other forms of players taking advantage of bugs (or each other). Both of these requirements add to the cost of developing and running massively multiplayer games.

The hybrid of single-player and massively multiplayer games I call the "Living World" game addresses both of these issues by building a single-player game inside a persistent world to be played for years.

A game designed to be played for years will need new content throughout that time. MMORPGs show us that this content provision can be monetized. This not only creates a more steady revenue stream than the much riskier hit-based model of single-player games, the normal and accepted registration requirement of online games should reduce the incidence of piracy as a proportion of total revenue-generation opportunities. At the same time, structuring the gameplay for individual players reduces development and operational costs by eliminating the need for special-case code to prevent griefing by other players or to address undesirable emergent social effects. This allows a more dedicated focus on the relatively simpler goal of a satisfying play experience for one person at a time.

Not all the advantages for this kind of game accrue to its developer and publisher. From the player's point of view, rather than being like the cotton candy of many single-player games -- insubstantial and quickly forgotten -- a Living World game would be a highly memorable place that the gamer could return to at any time, whether for new adventures or for a sense of coming home to something familiar. It would also have the advantage of letting the player be the sole hero, free to advance at his own preferred rate (or not at all) rather than being merely one client among many, easily abused by those who've been playing longer.

Those, then, are the key arguments in favor of producing a single-player, persistent-world RPG that could be not just played in but lived in for years.

Let's now consider some of the specific design possibilities and issues a Living World game might face.

Enormous area to explore

The map of a Living World game would require weeks (real-time) to traverse by a character traveling as rapidly as possible. This would insure that the game contains unknown places for a long time.

Rather than the entire gameworld sharing a single culture (and language), in a huge gameworld there could be places where the player character simply would not be able to go (at least for a while) due to limitations on travel speed, cultural biases ("you can't come in; our country is at war with your country") or simply not knowing the local language. This allows for a very extended process of world exploration, giving the player a reason to keep coming back to the gameworld over a long time.

A dynamic world

As in a MMORPG, time in the Living World CRPG would continue to pass even when the player is not actively playing.

NPCs could die of old age and be replaced in their roles (perhaps in some cases by their descendants). As years pass in the game world, NPC behaviors in the aggregate could alter some parts of the game environment. In prosperous areas, some settlements or colonies could grow into stable habitations. In poor areas, or as a result of famine, disease, or war, some settlements could be abandoned, later to be occupied by barbaric/native NPCs or reclaimed by nature.

Allowing such changes due to the passage of time in a persistent world has pros and cons. While it would support the feeling that the game world is a real place whose existence is independent of the player, long-term changes in creature and NPC populations could upset narrative- and roleplay-focused gamers who form emotional connections with some strongly-realized NPCs. Providing in-game tools for discovering and understanding change, such as genealogical charts and "newspapers," could help players whose enjoyment of a gameworld comes in part from feeling connected with the characters in it.

Letting the gameworld change also provides a mechanism for refreshing content -- as the player explores the game world, changing it by his actions then moving on, explored content can be repopulated or even replaced. (This could be done by the game itself, or through content updates, or -- preferably -- both. More on this in a few moments.)

However, "change" in a Living World game will probably need to be restricted to prevent NPC inventiveness. A medieval-era fantasy Living World, for example, should probably not be allowed to invent itself into a Renaissance or Industrial Age or later, since this would require developers to create launch-time assets that players might not see for years... and where do you stop the march of progress? This restriction on NPC creativity is likely to make the game less satisfying to dedicated Simulationists. Still, this could create opportunities to deliver subsequent cultural/technological eras, with their modifications to code, art, sound and other assets, as major expansion packs to the original game.

Environmental, ecological and social simulation

A Living World game probably needs to have extensive simulation capabilities, both to provide dynamic content for exploring while the player is in the game and to allow the gameworld to appear to persist (and change) when the player isn't in the game.

Environmental simulation means modeling macro-level physical phenomena such as stellar types, local gravity, rotation and orbital periods, seasons, day/night cycles, tectonics, mineralogy, topography, atmospheric composition, temperature, hydrography, geographically appropriate weather, and native lifeforms appropriate to their environments.

Ecological simulation will reflect the effects and movement over time of groups of living things as they live, reproduce and die in large numbers. Plant types and animal populations might vary in type and location due to changes in habitat over many in-game years. Humanoid populations would move to follow more attractive conditions and better food supplies -- players who are out of the game for a while might return to find that a village they once visited had been abandoned. (Some places should be exempt from such changes in order to insure that a player has a secure place to store valuable items between play sessions.)

Social simulation would model high-level cultural changes. These would include changes in the opinions of NPC factions toward each other, and possibly even the automated extinction, merging, and creation of factions as small as towns and as large as nations. Social simulation would also model large-scale economic, military and cultural behaviors. This level of simulation would be extremely useful in creating a dynamic gameworld that can change enough to be interesting over the long (real-world) term.

Constantly refreshing active content

A Living World game would need some way to refresh existing active content. (I use the word "active" to mean content with which players interact directly as gameplay, rather than content which changes on its own to mimic a dynamic world.)

Randomly-generated active content that looks good and plays well might be possible for some definitions of "active content" such as puzzles. More conventional content, however, such as quests given by and including memorable NPCs, would be very difficult to create in this way -- for example, where would the audio dialogue come from for an NPC who's part of a dynamically generated quest?

A Living World game could also be designed to allow players to create content for themselves and others, using some combination of the world-building tools available for games like Neverwinter Nights and Morrowind and the content-rating system of Spore to refresh some game content with high-quality replacements.

But I believe developer-generated content would be the best way for a Living World game developer to go. As with MMORPGs, providing a Living World game with a steady stream of new content and enhancements long after the core game is purchased and installed could be a successful business model for a developer. Players would be assured of getting high-quality new content (including professional voice acting), while the developer would gain the long-term revenue stream that would help to pay back the costs of developing a Living World game.

Truly epic storylines

An opportunity uniquely afforded by a Living World game would be the chance to tell significantly larger and more complex stories than those found in other kinds of games. A large and complex gameworld which can't be affected by hundreds of other players creates a broad but relatively stable framework on which to hang stories of great scope.

An interesting possibility here would be to provide players with several outlines of epic stories. Once an epic is selected, large-scale world-changing events are set into motion, and before long the player will be impacted in some way. Epics could be story-based (the princess is in love with a prince of the neighboring enemy country and needs your help), action-oriented (barbarian/alien invasion), or adventure-driven (find a way to appease the angry god who's disrupting the world with volcanoes). But in all cases, starting an epic will reshape the physical and/or social structures of the game world in some way that affects (and can be affected by) the player's character.

Customizable rules

As noted above, some players might prefer a world in which NPCs don't die. Other players, however, might enjoy seeing NPCs who die be replaced. Players might wish for more or less aggressive NPC cultures, more or less environmental variation, and so on. A Living World game might allow these aspects and other rules governing world-behavior to be optional -- something else a massively multiplayer game can't do.

...

Obviously there'd be a lot of work necessary to put some real meat on these bones of an idea. Numerous novel problems would need to be solved.

But I'd be interested in hearing what people think of the basic concept. Does the business model of shifting revenue from the one-time purchase of a single-player game to the ongoing content enhancements of MMORPGs (while retaining a single-player focus) seem plausible? What about the gameplay -- would there be enough gamers interested in something like this to pay back its likely development costs?

In short, is there enough vigor in this hybrid to survive in the competitive environment that is today's computer game industry?

Thanks for reading!

(Note: This article was adapted from a version originally published on an older blog of mine.)