Here is the full list of all 15 Heroes of Loot achievements.
Drink from the well
Buy a titanium shield
Get the "Lens of secret"
Unlocked Barbarian character
Kill a minotaur
Play in the Arena room
Activate a statue
Maximise dungeon difficulty
Reach dungeon level 15
Become level 10
Become invisible
Kill a cyclops
Save a lost soul
Upgrade the difficulty of the dungeon
Slay 5000 monsters