Sensory Input and Feedback
One easily recognizable factor that can draw a player into the game world is enhanced sensory interaction. Virtual reality systems immerse the player's visual and auditory senses in the game by offering 3D graphics and stereo sound. Players feel that they are physically in the game world. The sensory experience does not have to be computer-generated; many games use role-play in a real environment to create the immersion experience. For example, military training uses simulations of combat situations involving real people, weapons and scenarios.
Narrative
Another factor that can immerse players in the game is the use of a provocative, engaging story. The success of some well-known video games demonstrates this principle. For instance, the Halo series centers on a war between humans and aliens. An engaging story in a game works much the same way as an engaging novel; players want to know what happens next and have an emotional investment in the development of characters and environment. However, in the game world, players can actually influence the story's outcome.
Strategy
Strategy to win can pull players into the game even if there isn't a narrative and the game offers minimal sensory feedback. Players concentrating on their strategies to win the game can become so immersed that they close out distracting and external stimuli. One example of a game that uses strategy to create immersion is chess.
Social Interaction
Immersion games can allow players to interact with each other freely -- even when they are miles away from each other. Chat boxes, global chat rooms and voice over Internet protocol systems allow video-game players to form teams and communicate with each other. Many computer games incorporate team play with complex social interaction. PlayStation 3 has voice over Internet protocol services through some games (such as "Call of Duty"), and the multi-player online game "World of Warcraft" includes a similar voice service, as well as team and global chat rooms.