Here is the full list of all 29 Dungeon Girl achievements.
Unlocked all achievements in Dungeon Girl
Entered the dungeon for the first time
Found the first dungeon exit
Defeated the first dungeon boss
Crafted an item for the first time
Cleared 100 floors of the dungeon
Cleared 200 floors of the dungeon
Cleared 400 floors of the dungeon
Cleared 800 floors of the dungeon
Discovered the reason for the dungeon's existence
Unlock Marietta as Friend
Unlock Eve as Friend
Unlock Nine as Friend
Unlock Rakumo as Friend
Unlock Ite as Friend
Unlocked Level as Friend
Unlocked Tico as Friend
Unlocked all Friends
Unlocked all Types
Completed Item Inventory
Completed Enemy Inventory
Unlocked an extra Story with Friend Points
Unlocked a new character with Friend Points
Fully completed a character's Friend Map
Have a full grid of Attack panels and use it to hit an enemy
Gather 99 Keys, 99 Loot and 99 Treasures in one dungeon dive
Recover from 1% Mind without having to escape dungeon
Use Stairs when facing 5 enemies
Created a rarity 9 item from lower ingredients