I think what I love about this dungeon is how it tells it's story concisely and through the rooms, with very little descriptive text.
Short paragraph explaining the book, which is pretty good.
Some hazards in the mouth, with less than 10 words of description of each, but enough to run with. The illustrated map also provides plenty of inspiration for narrating the progression through the creature.
The suggestion that someone was controlling the thing, then a trip through the digestive tract to learn that it was felled by the fungi and rescue villagers. The chance to successfully rescue the missing people is important for the players to feel accomplished.
And then you find the wizard? who was controlling the beast with enough breath left to explain what the fuck happened. Then you have to crawl through a "tunnel" to escape.
Good stuff. More adventures should accomplish as much with as little.
I don't have a lot of cash instructive feedback beyond my praise. Explaining exactly what the "Toxic Spore" special ability does might be useful since it's a combat ability. The other vague references are fine by me as I can just assign a random infection and damage that seems reasonable, but combat abilities demand a little more explaination in my opinion.