The whole difficulty of FF1 seems to be up a couple of pegs for WSC/PSX version. Brian Carper's recommended levels for most dungeons seem pretty low. As an example with my Fi/T/Wm/Bm party at level 14 I was getting creamed on the third level of the earth cave, despite having a load of Potions, all spells bought and the best equipment possible at that point in the game (without visiting Crescent Lake)