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