I really like the concept of the horror here. The lo-fi, DIY aesthetic of the pamphlet mostly works, with some minor exceptions. The environment is decently detailed and there are enough NPCs to keep things interesting in between the action sequences.
The biggest weakness is organization and ordering of information. Everything seems to have just been put wherever it will fit without much thought given to what order the would-be Warden is going to read things in. It's not clear whether this is meant to be roll fold or Z-fold, but either way it doesn't really work.
I assumed roll fold, so after the front cover I went to the left panel/inner flap and immediately encountered... Zoicha's cassette? Who's Zoicha? What's this lake she's talking about?
The most important information seems to be in the TOMBS section at the bottom of the middle panel, which is the last thing someone would see for a roll fold.
Okay, they're drilling wells, and suddenly there's tongues coming out of the lake. That's what I needed to know first,and less cryptically/poetically than you're presenting it. I appreciate that you're trying to be artsy/moody at times but it takes really refined writing to execute that without becoming confusing, so I would default to writing in a more direct and straightforward style for the important sections. (Side note: this is the second time I've seen someone explicitly include their TOMBS structure in a module, but I don't think that's the intent of the tool. It's a way to think about things as you're designing your scenario, not a recommendation for how to present the story to someone else.)
It would go a long way to replace the TOMBS section with the standard "What the players know" followed by "What the players don't know" sections, and put that on whatever panel you expect people to see first after the cover.
The interior spread is better but there are still usability issues. The outpost map uses symbols from the Shipbreakers' Toolkit without a key explaining them. I wouldn't assume the reader is familiar with any material other than the PSG, unless you're going to say "This module requires [XYZ] to play."
The index card with the encounter table is the one bit of "DIY aesthetic" I don't like, as the other things are all potentially "in-world" materials, whereas a D100 roll table isn't something you'd find lying around the base in-game. So having that presented that way is jarring and spoils the aesthetic. I think it could also be made more clear that this is for use during stages 4-6 on the timeline, not locations 4-6. Presenting it beside the location key made me think locations, so this is another example of needing to think about how you organize the information, keeping things that go together physically together in the pamphlet.
Anyway, having now thought through everything and re-read several times, I think I have enough of a handle on the scenario to run it, and it's pretty cool. But it was a lot of work to get to that point, so I would try to focus on making life easy for the Warden on your next attempt.