Here is the full list of all 11 bit Dungeon III achievements.
All Archons have been defeated.
Hunt down 25 elite monsters.
High equipment rarity total has been reached.
Kill 100 Fiends
Free Sophia's Soul.
Assisted all neutral monsters.
Gain 50 souls from defeating bosses.
Kill 50 players and take their souls.
Equip all rune slots with rarity 3 and above.
Defeat the Monad in the Darkworld
Unlock the Shade race.