Used in many video games as both a game mechanic and as a story telling tool time travel is a go to concept for developers that want to add interest, intrigue or in some cases pure craziness. Some games use time travel in a canonical sense and have reasons for it, whereas others merely have it and it is just accepted that this manipulation of time is simply the mechanic of a video game.
Time Travel Types
The projection of a person’s consciousness in to the body of a person living in a different time. This form of time travel was popularized by the television show Quantum Leap. This form is used in most video games where time is rewound or reset, such as the Assassin's Creed series, the Prince of Persia series, Clannad, Radiant Historia, or Time Shift. People may see this as an alteration of time, yet it is indeed a form of time travel.
A more scientific variation of this concept can be seen in the science-adventure visual novel game Steins;Gate, where instead of rewinding or resetting time itself, the player character's mind is transported as data to his past self.
Full Body Transportation
The more widely used form of time travel popularized by the likes of Terminator and Back to the Future. A subject’s whole body is moved backwards or forwards in time, the result can lead to a person seeing themselves in the past. This form was used as a story mechanic in the many Dragon Ball games that cover the Android and Cell Sagas. It was also famously used in the classic role-playing game Chrono Trigger, and has more recently been used in World of Warcraft: The Burning Crusade where players are transported back in time to fight past battles.
Time Travel Consequences
Cause and Effect
The main time travel consequence, that what happens will change the present day. This can lead to paradoxical situations, such as that age old question of what would happen if you killed your own grandfather. Not really used much as it can be difficult to track and follow. However this definition could be applied to all video games that have time manipulation.
Pre-destined Time Travel
This is time travel that was always meant to happen. So the events of the person who traveled in to the past will have no effect on present events. This is used as the main plot point in Futurama the game.
One theory of time travel is that when a person travels back in time they actually create and alternate reality. This is a time line that splinters off from the original creating a whole new universe. This form of time travel is the easiest way to explain most time travel. It is used in games such as Command and Conquer Red Alert, the only way to explain it’s time travel story line without creating a whole host of paradoxes. It is also used as a main story point in the Android and Cell Sagas in Dragonball Z.
Most, if not all, time manipulation can be described as time travel due to the fact that controlling time would be rather more difficult. Instead when time is rewound in a game the consciousness of the “time manipulator” is moved backwards in time. When time is stopped or slowed the “time manipulator” is simply moving more slowly through time or has stopped moving through it. It could be possible to manipulate time, massive gravitational forces effect time in the same way that they bend space. Though, as stated before, it is much easier and simpler to travel through time. Though this is only if they have a canonical reason for the time manipulation, if it happened outside of the reality of the game, such as in Race Driver Grid, then it could be considered that time itself is being altered.
Lives and Game Saves as Time Travel
Traditional old school gaming with its lives could actually be considered time travel, when a character dies their body is put back in place at a predetermined location. They have traveled back to a time at which they were safe. This could then be considered a meta form of time travel. If this was taken a step further then game saves are quite literally a form of time manipulation within a game world. The player is resetting the clock back to a predetermined point, but with more active control than lives.