In The Sims 2, intelligence is embedded into objects in the environment, called "Smart Terrain". The objects broadcast properties to nearby agents to guide their behaviour. Each agent has various motivations and needs and each object in the terrain broadcasts how it can satisfy those needs. For example, a refrigerator broadcasts that it can satisfy hunger. When the agent takes the food from the refrigerator, the food broadcasts that it needs cooking and the microwave broadcasts that it can cook food. Consequently, the agent is guided from action to action by the environment.
The game objects in Half-Life 2 use named links, called "symbolic links", between pieces of content to define the properties of the objects and determine how they can be affected by players and other objects. Using this global design, the objects behave more realistically and are more interactive as they are encoded with types of behaviour and rules for interacting, rather than specific interactions in specific situations. These objects afford emergent behaviour and player interactions that were not necessarily foreseen by the developers.
In Oblivion, there are many independent characters, organisations, and quests, each with different motivations, roles, and possible interactions with the player. The world is also expansive and filled with many enemies, animals, objects, and places the player can visit. There is an extensive range of possible interactions, quests, and minor storylines, and it is unlikely that any two playing experiences will be identical. However, the game still hinges on a very linear, central storyline that the player must follow to complete the game. Although the world itself is open and varied, their choices and actions have little impact on the final outcome.
In Vampire, the player's actions and decisions throughout the game impact on how their story ends. Unlike previous games, it is not merely their final dialogue choice that decides the ending, but many choices along the way. The player has a far greater sense of agency and centrality to the game world, as their choices have consequences and they are actively changing the world and co-creating the story.
