The whole problem with any type of "timeparadox" questions,
is, that
the first analysis must be:
How should it be possible to turn back time?

If this can not be answered, the following
analysis is not valid, as it
might ignore mechanics of the nessecary first analysis.

Some small recent games of mine:
Griefer 4k http://damocles11.byethost9.com/griefer4k.html
Kobold 4k http://damocles11.byethost9.com/kobold.html
Cave 4k http://damocles11.byethost9.com/cave4k.html