Here is the full list of all 38 Ziggurat achievements.
Unlock all character classes
Get to floor 3 using only the magic wand (Apprentice class only)
Find all lore scrolls
Unlock all enemies in the bestiary
Kill all enemies at least once (including bosses)
Kill 5000 enemies
Kill 500 enemies affected with elemental states
Break 2,000 things (Barrels, tombs...)
Find a super secret cheat code
Die 10 times
You met your match in the final showdown
You died on a danger room
Kill a Lost soul with the Skull of Xanatos
Survive the Ziggurat
Reach experience level 15
Kill 1000 enemies
Master a perk by getting it to level 5
Equip a weapon of every kind
Reach experience level 10
You reached 3rd floor. Now the real lesson begins.
You've been ambushed in a treasure room
Reach experience level 5
Find your first amulet
Complete a challenge room
Find a secret room
Get your first level up
Unlock all magic weapons
Unlock all perks
Unlock all weapons,perks,lore & character classes
Die 25 times
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
Died after killing the boss
Unlock all amulets
Win the game with Argo on Normal difficulty in less than 45 minutes