In response to comment by pushcx on Causal Universes
Comment author: Ritalin 01 December 2012 09:44:32PM *  0 points [-]

If, one hour later, Marty does not activate his Time-Turner, the universe fails its consistency check and is deleted. If Marty does activate it, the universe looks back at the Marty that was added an hour ago. If the two Martys are not bit-for-bit (at whatever the lowest scale of the computation is), the universe fails its consistency check and is deleted.

fails its consistency check and is deleted

By whom? The DM? Jokes aside, how does that happen, exactly?

(As a matter of fact, that could be an amusing mechanic to add to games that allow for time travel, though the players would be stuck in a Groundhog Day Loop until they pass the check).

In response to comment by Ritalin on Causal Universes
Comment author: kukurio 10 December 2012 02:01:39PM 5 points [-]

There is a game which does exactly this. It's called Chronotron, and you play a time-traveling robot who has to create multiple versions of himself via time travel in order to complete each stage. The loop must be closed for all iterations, though, which means that if a future version of himself interacts with a past version of himself in such a way that the past version is prevented from going back in time, you lose the stage and have to start over.

Pretty fun game, although since it's a Flash game it's relatively short.