Permadeath determines whether your character's death is permanent, or just an irritating inconvenience.
There are 3 Permadeath settings in the game:
This is the default setting. You get up to 7 extra lives, gaining one at experience levels 1, 2, 5, 7, 14, 24, and 35. Dying (with extra lives still unused) sends you to the Eidolon Plane.
On Roguelike, when you die your game is over, unless you have alternate means of resurrection. "You *are* your character."
Exploration is infinite lives, and is only available if you are on-line and are marked as a donator on the server. Once you start your game (and save) you can play offline. Exploration mode has its own set of Achievements. Playing on Exploration does not prevent unlocking things.