I have a great time playing through all sorts of game worlds—blasting randomly placed enemies, collecting scattered power-ups, earning points, gaining levels, all en route to some nefarious “main boss.” Usually the game world is very transparent though, meaning I can tell I’m in a game from the moment I pick up a controller to the moment I put it down again. As a player, I’m not exploring environments, I’m beating levels. I’m not fighting aliens, I’m defeating scripting.

This isn’t always the case. Sometimes I can forget I’m playing a game. Sometimes I feel I really am crawling through an air vent in the Black Mesa Facility. Sometimes I think I’m actually looking for the orc chieftain who has been leading the attacks on my village. Sometimes I—

Wait! Whoa, let me back up for a second. I’m afraid I’m giving you the wrong idea here. I’m not one of those immersion freaks who speak in character in MMO general chat. (“Lo, I am Beragond, son of Herengar, from the House of—.”)

Please don’t think that.

All I’m trying to say is that sometimes a game feels like levels and sometimes it fells like a world. Do you know what I mean? The difference is subtle but important. I have fun playing either way—the game play “works” regardless—but the times that I feel I’m in an actual world, as opposed to digitized geometry, are the times I remember most. Those are the experiences that keep me gaming.

I’ve compiled notes on the conditions that enhance, or at least encourage, the feeling that a game’s environment is a real place, that it may theoretically exist somewhere out there and is not just a collection of levels built solely for my amusement. Surprisingly, this kind of immersion has little to do with graphics (though good graphics never hurt, they are not the focus of this article). It has more to do with subtle elements borrowed from the real world. My notes on well-constructed believable game worlds, derived from many, many hours of video games played since I was a tricycle-riding youth, are summarized below into three main points. Strangely enough, all three points relate directly to ecology. Think of this article as an attempt to preach the basic ecology of video game world building.

If you design sports games, or maybe puzzle games, you can probably give this article a skip. But if you’re a world builder, the kind of designer who strives to create exciting and believable environments, no matter how alien or bizarre, then read on. This article will give you three simple guidelines you can use to make your game worlds that much more believable, and therefore that much more exciting to play through.

1) Creatures are Part of Their Environments

Begin the level design process with your Non Player Characters (NPCs) in mind

I’m going to use the term “ecology” very loosely here, so loosely that it need not necessarily apply to creatures that are alive in the strictest biological sense. In other words, and this disclaimer is really only necessary in a discussion of video game world building theory, the ecological patterns I’m about to describe can apply to creatures that are not specifically alive, creatures such as undead zombies, self-replicating robots, puddles of sentient ooze… or whatever other imaginative aberrations your particular game may place between the hero and the much-feared main boss!

In any case, regardless of your particular brand of bad guy, you should always remember two things. 1) creatures are part of their environments and, as an ancillary rule, 2) creatures shape, and are shaped by, their environments. What I mean here is that creatures do not exist in a vacuum. When a player encounters a creature in a game world, that creature should, at a glance, appear to belong in its environment. Communicating, or at least implying, the connection between a creature and its environment is often far easier then most game designers realize. There are several ways to do this including: environmental associations, contextual events, or even simply the visual appearance of the NPC model itself.

The easiest of the tools that can be used to tie creatures into their world come from environmental associations between the creature and the surrounding game geometry. In other words, wherever a creature appears in game, it should be nearby an object (or objects) typically associated with that creature type.

In the World of Warcraft, for example, the Silithids (a race of giant-insect creatures) build hive mounds and strange claw-like chitin towers wherever they go. These architectural structures even look like silithid-shells, implying that they were made, or perhaps grown, by the creatures that live in and around them. The end result is that whenever players see these structures from afar, they know silithids are nearby—this kind of logic makes sense to explorers of the World of Warcraft—and so they are not surprised when they encounter an angry hive of giant bugs near the chitin towers.

A Silithid hive in World of Warcraft

The silithids are just one example of the many races in WoW that have unique types of game geometry which are used to visually tie creatures to their environments. World of Warcraft also utilizes unique dwellings for the furblogs (hollow logs and tribal banners drawn on animal skins), as well as for the murlocs (stilt houses built along shorelines). In fact, just about every sentient race in WoW has a unique type of architecture. Even the oozes have their green mud-puddles to crawl out of.

The end result is that very few creatures in WoW appear out of place. Nothing just appeared there out of nowhere. In fact, environmental associates give the appearance that these creatures have inhabited their environment long before the player arrived, thus giving the player the idea, at least subconsciously, that they are moving through a living, breathing world with its own patterns and consistency. More importantly however, the player is rarely surprised by the type of monster they find within any particular environment, which in turn reinforces the believability of the world as a whole. Compare this to the alternative—which is filling a forest with a randomly-placed medley of goblins and griffons or, worse yet, groups of goblins and griffons standing in an open field—and the advantages of environmental associations really stand out in their ability to convey a believable ecosystem. I’m not saying your game can’t have roving packs of creatures in otherwise unspoiled wilderness, I’m just saying that these kinds of encounters should not be the norm.