I've finished the Dungeons of Ivellon. Phew, what an experience! I must say this mod deserves its fame as one of the best dungeon mods of Oblivion - and I refrain from saying it's *the* best only because I don't know them all.
Anyway, it's a mod featuring a very well-constructed dungeon with an interesting story and a great sense of location - no uncoordinated sprawling here like in so many caves, sewers etc. It also fits so well into the world lore-wise that it feels like a part of the original game, except that it's so much better than the regular Oblivion dungeon-like places. The Dungeons of Ivellon are hard to find, reasonably hard to survive and most notably hard to get out of again, all of which makes the claim in the storyline that Ivellon is a legend nobody has been able to find for a long time believable.
I found the Dungeons of Ivellon a high-tension experience, from the point where you find the entrance right up to the point where you surface again. Even though most standard fights aren't that hard (at least, they weren't for my high-level mage), the ambience makes it so scary that the tension never ceases - even when you *know* you have killed all enemies in a level, it feels like more may be lurking around the next corner. When you surface again, you actually feel you're glad seeing the sky. Games rarely get that immersive!
@L@zarus:
Thanks for the hint, but it came too late. I bypassed that room, maybe I'll return to the place later. I think I found everything else, though, although I wonder about that book mentioned in the alchemist's notes... Now my character will go home, proudly display her complete set of Ivellon armor and weaponry in her trophy room at Aranmathi, and tell everyone who asks a story that won't be believed

I have experienced one technical difficulty: the boss of the crypts level was disabled when I first entered his place. I only found that something should exist here because his name showed up while exploring. I reloaded, and the second time he was there, but his AI was deactivated. I had to TAI him to continue.
And one more question: I'm wondering about the enchantments on the Ivellon weapons: "no effect on strike", it says. Is that as intended?