I'm very excited to see Echoes of the Overwatched released and can't wait to hear how the adventure plays out for everyone!
Looking at the adventure, I thought I'd chip in my thoughts about running the various acts. A few details were cut in development, generally to improve the pacing of the adventure.
In the first act, the PCs investigate what's gone wrong in the Blakros Museum. When they poke around in the attics, I'd have the dangerous floor section creak ominously, but hold until violent movement collapses it (such as when someone rushes in or out of the chamber). The nature of the threat within the observatory may be unclear at first: If the party fears that they face an invisible opponent, they may try to retreat from the room or rush in. (In one of my rough drafts, the haunt had a fear effect to drive victims onto the trap, but that just wasn't nice!)
To give the party the sense that time may be of the essence, I'd mention that its about 2 PM when they wrap up in the museum. Dark clouds churn above the city, promising rain in the evening. Gusty winds carry the scent of the sea, as the forlorn cries of birds draft above. (Yes, I like a bit of purple prose when setting the mood...)
To keep the party from spending too much time on their investigation, that section of the adventure was abbreviated. I agree entirely with the developers' decision to get the PCs into the "meat" of the adventure, but gamemasters who wish to extend the PCs pursuit can include rumors of additional murders committed by the Devourer of Reason as it navigated the city. Additional encounters may make the scenario run quite long, so GMs should be wary of including them.
Some PCs may want to involve the local Watch: The Learned Guard protects the Wise District, headed by Mendhir the Colossus, a member of the Society and semi-retired venture-captain. Those seeking him out find him sympathetic: He assigns a squad to watch over the area near the museum, but lacks the resources to give further aid.
(I'll add more later, if people are interested...)