It's unforgiving and very exhausting, no arguing there. It's because there is a complete lack of any kind of help along the way. No healing springs, no save points. You treck through one enormous dungeon, surviving only on your items and spells, face a tough boss, only to go through an even harder dungeon, facing four of the toughest mothersmurfers in the entire series, before finally battling one of the most unforgiving final bosses ever (Cloud of Darkness on the NES, though easy in terms of strategy as she only has one attack, nevertheless is brutal), all without being able to save or heal up even once. I can definately see why that would be considered to be the hardest final dungeon in the series and I agree with that. It's a good thing that both Syrcus Tower and World of Darkness are so epic that makes players *want* to take on the exhausting challenge.