This a staggering amount of content, it's impressive you were able to accomplish this in the time allotted!
I thought you nailed the classic look of the cover. The artwork is all great, a nice addition could be illustrations for some of the more interesting locations like 88. Lurbash's Room or 97. Glass vats, or some of the Special Treasures - I'd like to see what you had in mind for the sci-fi tech.
As with most mega-dungeons I would probably cut out some of the emptier rooms and combine some of them together, but you did a good job keeping the content varied. I appreciated that the descriptions were straight to the point and very usable at a table.
It doesn't take away from the work, but the Table of Contents appears to be broken in the PDF.
Viewing post in The Obsidian Ziggurat jam comments
Thank you for the most in-depth critique I've gotten so far, very much appreciated. I definitely will consider the possibility of adding more illustrations in future updates. We had planned to include art of the leaders of each faction at the very least, but ran out of time.
About the table of contents thing... I actually don't remember generating a table of contents for this. The file is made out of four individual PDFs so my guess is that the program I used to stitch them together and export them as a single file probably automatically generated a table of contents for it.