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