Here is the full list of all 35 Avernum: Escape From the Pit achievements.
Complete all three game-winning quests in Avernum and never set the difficulty below Normal.
Discover a route back to the surface world. There must be one somewhere.
Destroy the demon Grah-Hoth, making Avernum safe from his menace at last.
Deliver harsh vengeance to the cruel tyrant who sent the Avernites into the underworld.
Learn 6 mage spells at level 3.
Reform a legendary blade from Avernum's past.
Find the secret at the bottom of Lost Bahssikava.
Join the Scimitar.
Learn 6 priest spells at level 3.
Avernum has five dragons. See if you can whittle that down a bit.
Purge a certain powerful demon from the Tower of Magi. Phew. Hope they stay out of trouble in the future.
Get a dread curse. Then cure it.
Sss-Thsss will trouble Avernum no longer.
Find something that lets you fly.
Meet the Archmage Erika.
Discover 50 locations of interest.
Steal the treasure from Gremlin's Gold.
Have ten potions made.
Enter the Castle at last.
Dig up 5 caches.
Slay 1000 foes.
Learn a mage spell at level 3.
Learn a priest spell at level 3.
Discover 10 locations of interest.
The mayor of Formello lost something of great value. Recover it.
Open a secret door.
Slay 100 foes.
Purge a nefarious infiltrator from Silvar's sewers.
Escape the tunnels under Fort Avernum.
Learn 18 mage spells at level 3.
Learn 18 priest spells at level 3.
Dig up 40 caches.
Have fifty potions made.
Complete all three game-winning quests in Avernum and never set the difficulty below Hard.
Complete all three game-winning quests in Avernum and never set the difficulty below Torment.