Continuity: In the world of ruin, in Narshe, it is possible to get the Ragnarok Esper, and have a one-of-a-kind sword made out of it. Later on in the game, it is possible to steal the same sword from an enemy.
Miscellaneous: The evasion stat is useless. All evasion is calculated with the MBLOCK stat instead. This also makes the beads relic worthless. This error exists on the SNES and PSX incarnations, although there are ROM patches for the SNES version to fix this.
Revealing mistakes: In the Cult Tower, you can faintly see through the windows out to the background, even though you should be seeing the inside of the wall.