I think this is a solid, well-written little dungeon. Seems very straightforward to drop into a game.
I like the random encounters, but I do think maybe they could be jazzed up a little bit. I really like the mushroom folk encounter, so as an example, maybe add that they searching for the Ordo Terragnis blade which could spin off into its own follow up encounter/adventure if the party manages to get it. I know space and word count is a limiting factor in how much each encounter can be described, but that's the one thing I can point to that I think could be more exciting.