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