This scenario has an interesting story, engaging NPCs and interesting interactions with the lore of the world. That alone would normally be enough to earn it a thoroughly good rating - however, it also has an extremely entertaining premise that continues throughout the scenario, which elevates it to certainly 5 stars territory!
This is definitely my favourite of the 3 scenarios. I love the final boons available, I love the choices that have to be made, and I love how it's actually pretty open-ended in the way it worked. I really have almost no criticisms of this scenario - it's just excellent. It's sufficiently challenging if you do it smartly, if you are murder-hobo-y in your approach, you make it that much harder. I love it!
The decision with Alexayn at the start is an interesting one I feel, and then again with decision with Suliji is tricky. I had two Paladins in my group, which made them harder again. The combat against Mr. Kahyn is painful for a lot of PCs - sundering isn't used commonly by enemies, and if you're running Hard mode those Wishes are just crazy powerful.
My only issue with this one is that the VC missions you can send people on seem ... odd. The only option is to send your underlings on what is basically a suicidal mission into the Aspis headquarters - if they went in the front door, they'd be facing a CR 15+ encounter straight away, realistically. My PCs obviously had issues with this, and wanted to get the local authorities to intervene - warn them that a killer was on the loose inside the building. I'd like some other options than 'suicide mission into the building or nothing', personally.
Almost a perfect scenario to me, however - excellent, truly.
Overall, I love the ambiance of this scenario - it's great fun, and the area it covers is both creepy and awesome. It can be quite a challenging scenario - Hard mode is much worse here than part 1. I did, however, have some issues with it:
This scenario did have some issues with presuming that buffs that are really very common would not be occurring. The final encounter basically operates entirely on the presumption that Flying isn't occurring - one of my PCs even had a permanent, non-magical flight means as an aasimar. This effectively trivialized the encounter, which was a little sad, for a cool encounter. The save DCs for the final fight was also a bit low, I feel, given that's the main thing I could use to attack flying PCs. The first combat encounter was a much more challenging one - a little more space would probably be better, as it could attack the more vulnerable creatures more easily.
I've just finished GMing this whole series down in Australia, and they were excellent. Part 1 was an awesome introduction - the first combat has the possibility to be pretty brutal, and is certainly different from almost any other combat in a published scenario. The mechanic for being a VC is cool - if your players are into roleplaying, I'd make sure you have time for it. Sometimes it's not obvious what possibilities there are, but you're allowed to be flexible about it. I really love the final fight in this part - an absolutely awesome idea.
I have only one real issue with the scenario:
Almost the entire scenario can be overcome by Freedom of Movement. The dimensional shamblers rely on grappling, spending an entire round grappled and then being alive to plane-shift away, which is an issue with freedom of movement - can break the encounter a bit, as the oracle is much less powerful on the Material plane. Similarly, the final fight wants a PC to be grappled to maximize the breath weapon, which is nullified by Freedom of Movement.