I have no idea how any group of characters makes it through A2: Secret of the Slavers’ Stockade without many deaths or permanent disfigurements. This module is extremely difficult; maybe those players who played it when it was released at Gencon in 1980 were ten times better at rolling than I ever was. And if so, good for them.
The first part of the adventure is a bunch of hobgoblins, which are fine, and an anhkheg, which is less fine, but still should be no problem. The real problem in Secret are the big bads that are introduced later. Down there, hanging out with the boggles and the hobgoblins that are disguised as mummies are Markessa who is a 5th-level multi-classed fighter/magic-user, Icar the blind fighter, his ogre buddy Executioner, and Blackthorn the ogre magi. Tough times indeed.
A 7′ tall, black man in black plate mail armor is poking and turning the roasting lizard with a two handed sword. He turns to face the door, as the party enters, and you see that his helm has no eyeholes. At a table in the east end of the room sit three barbaric looking men, all bristly bearded with coarse red hair. They have mugs of beer in their left hands and smilingly lift hand axes off the tabletop and hurl them at the party.
Also, there are wereboars.