Creating a file that completely describes all of the variables in a game, including location of units, states, mission status and inventory items.
Accessing saved games allows players to both:
- Leave the game, and come back later, creating an infinite length pause (called bookmarking in SCORM-speak), or
- "start-over” from that point, presumably to try new tactics or strategies, or maybe even relive a great sequence.
Saving a game (and the corresponding “three lives” granted in an arcade style game) represents the purist departure from a game/simulation and reality. It necessarily breaks the illusion of the experience. It also changes behaviors, rewarding high-risk behavior. (Funnily enough, in the old arcade games, there was a real financial consequence to dying.) And yet for-entertainment simulation require the contrivance, and even the most pure simulation-hawk would advocate practicing in a sim by replaying a situation over and over until mastered, as one might with a tennis backboard or batting cage.
Some strategy games, like Rise of Nations, have campaign modes that do not allow players to “backtrack” via save games. Players have to live with the consequences.
Some science fiction games, such as System Shock 2, have tried to work the notion of save games into the story using re-incarnation machines when the player dies.
The more open-ended a game is, the larger the save file.
A technique that only allows a player to save their progress at pre-established triggers, such as after a completed task, rather than whenever they want. This increases the suspense and the sense of jeopardy for the player, but can lead to frustration if the player has to replay a same sequence over and over again, especially if the sequence includes some linear aspects (especially pedagogical), and/or easy, repetitive play. Educational simulations have stricter save game policies than computer games.
One variation: some games save the game automatically and invisibly to the player. Clever designers put automatic save points before a difficult challenge to keep the player from having to backtrack too far, or right after a new level has been loaded, preventing the player from having to wait a second time as the level reloads. Automatic save points do not preclude open ended saving options.