Here is the full list of all 35 Avernum: Escape From the Pit achievements.
Destroy the demon Grah-Hoth, making Avernum safe from his menace at last.
Discover a route back to the surface world. There must be one somewhere.
Reform a legendary blade from Avernum's past.
Learn 6 mage spells at level 3.
Find something that lets you fly.
Find the secret at the bottom of Lost Bahssikava.
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.
Meet the Archmage Erika.
Join the Scimitar.
Steal the treasure from Gremlin's Gold.
Get a dread curse. Then cure it.
Sss-Thsss will trouble Avernum no longer.
Learn 6 priest spells at level 3.
Discover 50 locations of interest.
Have ten potions made.
Dig up 5 caches.
Slay 1000 foes.
Learn a mage spell at level 3.
Learn a priest spell at level 3.
Enter the Castle at last.
The mayor of Formello lost something of great value. Recover it.
Discover 10 locations of interest.
Purge a nefarious infiltrator from Silvar's sewers.
Slay 100 foes.
Open a secret door.
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.
Deliver harsh vengeance to the cruel tyrant who sent the Avernites into the underworld.
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.