The game won't let you exit the castle, no matter how you try. Technically you can win, but there is no end.

ARTEFACTS AND CURSES

Opal VS Blindness - you forget the map and don't see any new rooms, flares become useless
Pearl VS Forgetfulness - you don't remember where have you been before
Ruby VS Lethargy - monsters get the first turn to attack
Diamond VS Weakness - you lose 1 strength point every 20 turns
Emerald VS Bad luck - your minimal attack power drop to 1 instead of 50% of strength value
Blue Fire VS Bookstuck - book sticks to your hands and you can't attack anyone in this state
Sign VS everything except Bookstuck

SPELLS

Web prevents the monster from attacking and lasts 0-3 turns. Costs 1 point of intelligence.
Fireball is obvious enough. Costs 2 points of intelligence.
IQ instantly kills your opponent if its intelligence is less than yours. Otherwise, you lose. This spell doesn't spend anything.