Here is the full list of all 26 Deathtrap Dungeon Trilogy achievements.
Complete the Creature Codex
Unlock all Titles
Fully upgrade all Luck dice
Destroy Agglax the Shadow Demon
Tell Baron Sukumvit what happened to his Nandibear
Pass 20 Skill Tests
Visit the Oracle
Win 5 Skirmish Battles
Win the pie eating competition
Travel to Zengis by boat
Hire an army to save the world
Solve the Port Blacksand murder mystery
Fully upgrade all Skill dice
Pass 20 Luck Tests
Find all of the Gold Rings in Trial of Champions
Walk through fire unharmed
Complete the first trial in Trial of Champions
Complete Armies of Death on Hero difficulty
Complete Armies of Death on Legend difficulty
Complete Armies of Death on Adventurer difficulty
Complete Deathtrap Dungeon
Complete 8 quests in any one book
Correctly answer two or more riddles in Deathtrap Dungeon
Find and rescue the prisoner in Deathtrap Dungeon
Defeat the Bloodbeast in Deathtrap Dungeon
Complete the first trial in Deathtrap Dungeon