Level 9 of my mini megadungeon is home to petrifying monstrosities, a “noble” court of wererats, and a massive worm (but not quite as massive as a purple worm – fortunately B/X D&D includes the smaller Caecilia which fills the same role while being a more appropriate challenge for this level).
The natural cave section on the northeast side of the map contains links up and down between the levels, and is also connected to the main level albeit through a secret door, essentially making these two sections separate.
I plan on having fun with this level, with the statuary everywhere from the victims of the petrifying main badguys of the level. And there’s the chance that some poor idiot character might make the mistake of incubating a cockatrice egg or three along the way.
Or you can download the high resolution version of the map by clicking on the image below.