Travelling into the past to alter the future is a fascinating concept, but has a unique set of problems and issues ...
Several existing IF games feature time travel as a major theme:
- First Things First (J. Robinson Wheeler)
- All Things Devours (Half sick of shadows)
- Tapestry (Daniel Ravipinto)
- Jigsaw (Graham Nelson)
Rules of time travel
The "rules" of time travel vary by game, but here are a few common ones.
- Your past self may not meet your future self. In All Things Devours, "time unravels" if this occurs. Not all games include the possibility of meeting yourself, however.
- No contradictions allowed. If there was a potato in the pot at 10:00am and you go back before that time and remove it, the same potato (or an identical looking one) had better be back in the pot again by ten o'clock. (An unusual solution to this problem is just to close your eyes so that you don't see it in the first place).
- Alternatively, contradictions may split the universe in two - one future in which an event does not happen, and one in which it does. The problem then may be to go back and undo the damage, restoring the future to the desired one (as in the movie Back to the Future II) - or the whole idea may be to change the past so that the current "future" is made better (cf. Trinity).
Time travel hints
- If you can go back to a time in your own life, perhaps you can do so repeatedly - so there are not only two of you, but three, or four ... without meeting yourself, there may still be a way to give something to another one of your selves.
- You may be able to help yourself in some way in the future. In the novel The Hitchhiker's Guide to the Galaxy, people pay for their incredibly expensive reservation at the Restaurant at the End of the Universe by investing a single penny and collecting the interest at the end of time.
- Knowledge of future events may also be an advantage (eg. the lottery numbers in tomorrow's draw).
- Time travel allows for some very bizarre possibilities. It would be possible to transport an object to the past and leave it there, or to communicate an idea to someone in the past. If an object is left there, then it will be that very same object in the future (which you then took back into the past) ... but then, who made the object ? And if an idea such as "how to create a teleportation device" is communicated to someone in the past, then that same knowledge in the future came from that person ... but then who was its inventor ?