I think here we have an Annihilation Authority Acceptance enjoyer, and I find this to be a really great way to bring the endless scrawling of the Crawler of the Tower (or is a Tunnel?) into an RPG campaign.
I salute that this module makes heavy reference to hex maps, but itself describes activity which could happen on any hex map. That is, the territory and events are not a *new and hidden part of the campaign world* but are instead overlayed atop it. This is good thought technology.
I like that the malign hex mechanic is referenced in the Omens and other sections as the inherent origin of some of the omens - it reinforces the relatedness of the phenomena, and also lets the DM be flexible/adaptive to the hexagonal regions of their own campaign.
I love a diagrammatic map for a Myth Site!
"Self-drowned" is an amazing adjective (Omens 02).