Ghosts of the Past: Dark Portal – possibly the longest LFR module name to date. I have not done a comprehensive study. Mark B. ran it; Jason B., Susan, Evil Tony, Alan and I played.
The adventure has a rep for being brutal. It really is. We happened to have the right people in place for the stairs fight: I had good necrotic resistance, so I could easily stay static while the warlock disabled the big defensive ability of the problem monster. So that was one of the mean encounters handled.
We also did fine on the last fight. There’s an obvious save or die mechanism available, and I really don’t think the author intended GMs to use it. If you leave that out, the fight becomes really mean but survivable. On the other hand, you don’t want to spring it on players who don’t like bad status effects.
Susan was playing her cleric, Laela, and she threw down Consecrated Ground once we had the situation mostly under control. That meant we could reliably keep her out of the worst of the status effects, and none of us were in any danger of dying. Plus Consecrated Ground is perfect for dealing with the never-ending stream of minions.
If we hadn’t had the right combination of abilities, though, there are a few places where that would have been super-tough. My theme for the week, huh? I think this one is fair, FWIW. It’s a special and it’s reasonable to make it difficult. The one failing is that it’s not really a single slot mod.