No kidding. Especially since you can't save after the Syrcus Tower and have to do the World of Darkness straight after, with 6 of the toughest bosses in the whole game, no save-points or well-springs... Huh, I just realised how hard this game was on the famicom. Still, it's tough as nails but not so far as to be unfair. Gaining a few levels will always work wonders if you're ever stuck.
It's still a playable (and enjoyable) experience to go through, even with the difficulty, something that (IMHO) can't be said of the other two famicom Final Fantasy games. (No auto-retargetting and no damage-on-enemy-display seriously smurf FF I and II up to unplayable levels.)