Here is the full list of all 38 Ziggurat achievements.
Unlock all character classes
Unlock all amulets
Win the game without using any level up
Break 2,000 things (Barrels, tombs...)
Unlock all enemies in the bestiary
Kill 5000 enemies
Find all lore scrolls
Find a super secret cheat code
Kill all enemies at least once (including bosses)
You met your match in the final showdown
Kill 500 enemies affected with elemental states
Reach floor 2 without getting damaged
Died after killing the boss
You died on a danger room
Find a secret room
Kill a Lost soul with the Skull of Xanatos
Get to floor 3 using only the magic wand (Apprentice class only)
Survive the Ziggurat
Master a perk by getting it to level 5
Kill 1000 enemies
You've been ambushed in a treasure room
Reach experience level 15
Equip a weapon of every kind
Complete a challenge room
Find your first amulet
Reach experience level 10
You reached 3rd floor. Now the real lesson begins.
Reach experience level 5
Get your first level up
Unlock all magic weapons
Unlock all perks
Unlock all weapons,perks,lore & character classes
Die 10 times
Die 25 times
Die 50 times
Win a game with every character (any difficulty)
Win a game on hard difficulty
Win the game with Argo on Normal difficulty in less than 45 minutes