The time that the game runs is based on your computer's clock. It is possible to shorten things by setting the clock ahead and then going back. Be wary though, occasionally people will die over this time. Note: Try doing this by an hour at a time at first to avoid death from disease or starvation. Also, when clearing the rubble by the bath, do not set the time ahead. The tablet pieces that you should get from clearing the rubble will disappear and there will be no other way to get them.