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