2005-07-11 00:08 UTC Moebius
Allan and I were talking and we came up with an interesting idea for a game. (If someone wants to implement this, go ahead.)
The game would be an ordinary first-person shooter or first-person adventure game. The twist is that after playing it for a while, the plot involves time travel back to the point in time where the game started (or close to it): and you can see your character going through the start of the game, doing exactly what you did. That is, the game would record every move, every action that the player did for the first part of the game, and then replay those actions in real time when you travel back in time.
The cool bit is that to keep the story consistent, under no circumstances can the "original you" ever see "time-travelling you", since you didn't see yourself when you first played through the level. Thus, the game would have to keep track of whether the "time-travelling you" is ever in the field of vision of the "original you", and if it is, the game is over: Time Paradox.
Twists on this could be that you also have to make sure that the environment is in the state that you originally found it; for instance if a bridge is broken when you first play, it has to be broken when the "original you" gets to it when the "time-travelling you" is playing, even if that means bringing it down yourself.
And you can take this further. Time travel again, this time with two "original you"s and you have to keep out of the field of vision of both of them.
And you could, once you know you have a time machine, say "ok I'll go back in a minute and set it up so that this happens"...
Technically this is quite feasible. Field of view is a solved problem (lots of computer games involve having to sneak around unseen near patrolling monsters, e.g.); as is recording everything you do and then replying it when you next visit the level (racing games often have "ghost cars" so you can train against yourself).
The hard part is coming up with a decent plot.