The game requires the player, through a first person view, to explore Castle Eternity. There are riddles on many of the castle walls, which give gameplay hints. There are also keys and pentacles hidden in various locations for the player to collect. Many rooms contain spirits which attack the player and reduce his or her health. The player's health (represented by a barbell where weights indicate the amount) is also the player's strength which is important for some puzzles. The player's only weapon is an unlimited supply of rocks to throw, but a single hit is sufficient to exorcise most of the spirits. The ultimate goal is to kill the boss spirit Magister (who can only be killed when all other spirits in the castle are destroyed) and thereby rescue the character's opposite number.