Heal spells always give you the maximum amount possible, until your current HP is full.
Hurt spells deal X damage (not always the maximum) to the monster, regardless of the monster's armor.
Sleep spells put the monster to sleep. The monster has an X in 15 chance of remaining asleep each turn.
+Damage spells increase your total attack damage by X percent until the end of the fight.
+Defense spells reduce the total damage you take from the monster by X percent until the end of each fight.