"Preserve" mode, if set when the character was created, cancels all "special"
level feelings, but allows "missed" artifacts to be "saved" by wandering
monsters and found again at a later time.  This only works for artifacts 
that you have not already identified.

"Maximize" mode, if set when the character was created, causes the race
and class stat bonuses to be applied as if they were equipment bonuses and
lowers the stats you can achieve beyond 18 at character creation.  This
usually makes the character harder at the beginning of the game, but easier
later on, since the stats are no longer limited to being 18/100 naturally
but instead possibly much higher, depending on race and class -- 18/150 or
even higher are quite possible.
