How long did it take to play this part of Doomsday Dawn (not counting preparation or character creation)?: It took my group about 5 and a half hours.
How long did it take to prepare this part of the adventure (time spent reading, gathering materials, etc.)?: About around 6ish hours including advertising. This could have probably been longer had it not been for Roll20 getting the add-on.
How many sessions did it take for you to play through this part of the adventure?: One luckily.
How many Hero Points (in total) did you give out during this part of the adventure?: I handed out seven. None of them were used though because the players would just forget about their existence.
How many times was a player character reduced to 0 Hit Points during this part of the adventure?: Four, but if we include animal companions five.
How many player characters were killed during this part of the adventure?: None thanks to luck and a proactive Cleric.
Some general notes from my end: If the players spot the Ooze then it's dead before half of them can even act.
Everything hits hard pretty easily.
Why do light sources not have a dim light radius? Low-light vision felt completely pointless without any sources of dim light.
The Mindfog Fungus feels pointless without any real danger to the hazard, a player walks up to it, gets confused, others notice, get the player away and then just ignore the room.
Needing to succeed multiple times to unlock something really drags things down, especially with high DCs that can easily break lockpicks and resetting any progress. It was much much easier for the players to break the doors in a few hits rather than deal with the locks.
The goblin commando is a beast with his ability to trip with his weapon. He was the first one to bring a player to 0.
Drakus was interesting. The +2 bonus from reverting allowed him to easily one turn down the barbarian. The Barbarian started tripping him to get the conditional bonus but even that was hard because of Drakus' high Reflex and high AC. Drakus starting by the altar also gives him an advantage of not being easily flanked. The +2 circumstance bonus also helped him out a lot against the Bard
General feeling after playing: All in all the players had fun and want to continue so they are making the fourth level characters for part two but were confused why they couldn't just keep playing the same characters especially when there's no real story reason why they couldn't be the same characters. I had fun myself though there were a lot of times where combat would start to drag because there was some specific condition that needed to be looked up and there are so many instances of everything in the book.
This is obviously late and I'm writing this up well after the session but I'll hopefully have the notes from my players as well to post here.