The player is a cursed traveler seeking peace.
 Each grave at the end of a level represents a fragment of his memories or a soul-saving point.
 The ghosts are the souls of those who failed to complete the journey.
 Some have lost their minds in the darkness, while others still wish to help.
 By accepting their aid, the player binds himself to the spirit world (increasing karma/luck).
 By refusing, he offends them, causing the spirit world to resist his progress (resulting in debuffs and a drop in luck).