Orczilla was meant to be a major boss fight but I reduced her to a background role as you reached her cavern later than I thought you would.
This tunnel was never planned out for so many adventurers to enter so a lot of things didn't come off.
Like the room with the Mycanids, so many people entered that room when really I wanted them to communicate with one or two in privacy. Then the druid who they were meant to bond with goes and commits suicide.
The Trolls should have done more damage but the dice just wouldn't roll right for me.
Tridris was itching for a fight but no-one was biting. Then when he went full Lich and Raybur felt it was his duty to fight him as a Cleric, everyone decided that they didn't have time and just left him to it. I was surprised by that as together you would have stood a chance, but one-on-one there was ever only going to be one winner.
Usually it's the players that have to think on their feet to react to what the DM throws at them, but in this case it seems like it was more the other way around. Which makes what you did even more awesome, but that should go without saying.
Not that I ever participated in any such thing before, but thinking that it's also because the timing of reaction was so loose but the whole thing had a deadline, while I'd say normally such things are played with a set schedule for turns, everyone available at the same time to play through certain portions, but with no time limit for the entire adventure, some possibly taking years to complete.
As for the Lich, I for one am a strictly PvE player... Somehow ended up acting against him at the very end, but only because the opportunity was too great to pass up, with the rings I had, and after having made no use of them. Granted, don't usually play with others at all, but in such rare cases, assume people will work together, or at least not get in each other's way if cooperation is off the table. If there are hostile ones, tend to hope they'll leave me alone, and do what I can to avoid getting on their radar.
But speaking of changed plans, early on, considering my choices of spells as well, I rather intended to keep out of the way, stay invisible and levitating (assuming both were possible) as much as possible, considering that ring Doc gave me from the start also teleport away in case of trouble, and make my way through secret places, possibly past wards as well, and see about finding a way to safety while staying away from the "real" action. But with such a crowd, seemed to be more safety in it.
Then, when trolls barred the way, was thinking to go around, through the statue room, and come out behind them, after the others who took that route, but somehow just ended up lending a hand in fighting when it came to it, and trying to figure out something to say each turn other than / alongside just "Calad uses his Wand of Acid Arrows", since that wand was all I had (originally selected for range and the fact that acid seemed the least likely to be resisted).
And then Doc did make me change my plan for the end. Well, first those three just looking out for themselves did, since I quite fancied that idea of levitating Cardan and having him breathe fire all over Orczilla and minions, with others maybe providing cover. But then, even after how they chose to go about it. with the Lich seeming not a threat if left alone, had just meant to point the rest to that trapdoor, if useful, and dispel any ward that might have been on it (seems like there were no wards here?), but then stay there, levitating out of reach, reapply Reflect Spells and Missiles, and try to wreak havok to clear the way for the others, with the wand, the ring and maybe charming the lesser enemies, knowing I could teleport out if things got sour or time ran out. But Doc said I followed the others through the trapdoor, so said all right, I'm with them to just rush to the end.
Admittedly, got a bit panicky when there was that post about attempting to sabotage the portal.
PS: Speaking of changed plans, I was saying that I meant to stay mostly invisible and look for secrets, and Invisibility and Detect Secrets were the 2 spells I had and never used.