[DGD] time travel

[Shentino]

My biggest wonder about time travel:

If you should consider time as just another dimension (say, dinosaurs versus
star trek) where the current millienium or epoch is just another coordinate
like what continent you are on, then time travel becomes passive, like in
Chrono Trigger.  Great for tourists.

However, if you want to let players count on being able to go back in
history and actually change it (and let's face it, players LOVE to ripple),
then you're going to have a mess on your hands dealing with causality, not
to mention data retention as you keep tabs on the mud's history for rollback
purposes.  A hard cap on how far back in time you could go would probably be
required, and you may of necessity need to make time travel such an insanely
hard skill that few but the gods could ever pull it off.

Also, the cascading rollback phenomenon would, unfortunately, be a ripe
target for griefers looking to force players to rollback, or at the very
least stall the mud while it processes "time wakes" that either
instantaneously rebuild the "future" up to the present, or otherwise march
forward through the time line until they assimilate and replay the present.

I'm guessing that you'd need to evaluate a player's performance somehow, and
then resimulate it NPC style in the event of a rollback and reroll forward.
Perhaps a "you feel strange and your vision gets hazy..." type message would
explain why, owing to the butterfly effect, your character happens to be in
china fighting a firedragon instead of in haiti digging up an ancient cursed
treasure.

Good heuristics and tracking of how skillfully a player acted in the past
would likely be a good guide for the game system on how his actions would
change if the "wave of time" were to wash over him again.

That said, making it happen would be a phenomenal accomplishment.