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