To interact with a video game the player needs some form of interface. For most people I know, it’s a given that a simpler interface is less cumbersome and thus presents a smaller barrier to entry, allowing players to access the game more easily. However, some people seem to operate under the assumption that a simple interface equals simple gameplay. I think many games have argued effectively that this is not the case.

Simple interface can still equate to complex gameplay. For instance, in games with light-sensitive AI, the player can hide more effectively by turning out a light. And pushing a button can be accomplished as a simple interface action. Thus, complex gameplay, with very interactive situations involving manipulating the AI’s level of awareness, can be accomplished with a single click.

Along with many others, I’ve argued that it’s possible to divorce complexity of interface from complexity of gameplay. Obviously, other game developers have put this simple idea to good use. And some have completely missed the point, engaging in overly complicated game interface design without any increase in complexity of gameplay.

But is it possible to take this a step further? Is it possible to deepen the richness of gameplay with zero additional interface?

Diablo 2 is a really good example. It’s completely addictive, the interface is really simple, and most players are at least familiar with the game.

In Diablo 2, the player (with a necromancer character) can summon and “unsummon” skeletons. Whenever the player summons a skeletal mage, some of his character’s magic energy is subtracted and a skeletal mage is created. This summoning spell also consumes an enemy corpse. The specific “type” of skeletal mage created is randomly determined. The potential skeletal mage types are cold, fire, lightning, and poison. All of this is accomplished with a fairly simple interface, which makes the game accessible.

The problem here is that sometimes one type of skeletal mage is more desirable than another. As an example, players like the cold based skeletal mages because, in addition to inflicting damage, they freeze the enemies in place. Further, the game could have been set up to tactically take advantage of different types of attacks versus different types of defenses, so if the player is fighting cold-based enemies, a fire-based skeletal mage might be more desirable. I’m not sure if Diablo 2 does this or not.

So currently, in Diablo 2, players will often summon skeleton mages, then unsummon those that are not cold based. Players continue re-summoning until they have an entire set of cold based skeletal mages. This emergent player strategy gets the job done and it keeps the interface of the game simple, but it annoys some players because they expend a lot of magic energy inefficiently.

The interface is so simple that it does not allow the player to choose which types of skeletons to create. The upside is the simplicity. The downside is the lack of strategic control.

One solution would have been to create a different summoning spell for each type of skeletal mage. The game already does this with regard to golems, for instance, each golem type is summoned with a distinctly different golem summoning spell. But this would have been cumbersome, equating to four times the spell icons.

By applying context sensitivity, the game could have allowed for greater player control (another way of saying greater strategic depth) without increasing the complexity of the interface. If the “class” of enemy corpse dictated the type of skeletal mage summoned, the game’s interface could have remained uncomplicated while providing the additional strategic depth. In other words, if the player wanted to summon a fire skeleton, he would cast the summoning spell on the corpse of a fire based enemy. For a poison based skeletal mage, the player would cast the spell on the corpse of a poison based enemy. Players who did not understand this could simple ignore it, casting the summoning spell on the next available enemy corpse and settling for the type of skeletal mage that was created.

Not only does this demonstrate the distinct separation between complexity of interface and complexity of gameplay, but additionally I think this is an example of “interface-less” gameplay complexity. It goes without saying that just dropping this system into Diablo 2 without making any other changes to the game would be problematic. The mix of creatures per area would have to be set up to allow the player frequent access to the corpse types he might need.

When viewed abstractly, this notion might be applied to numerous game features, increasing the depth of the game without harming the game’s accessibility.