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