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