Here is the full list of all 21 Stonegeon 迷石地牢 achievements.
First time into the ruins
Defeat the Boss [Grumpy Big Boar]
Defeat the Boss [Greedy Big Slime] on the 5th layer
Defeat the Boss [Giant Goblin] on the 10th layer
Defeat the Boss [Flame Lizard] on the 15th layer
Defeat the Boss [Combat Bear] on the 20th layer
Defeat the Boss [Giant Cactus Ball] on the 25th layer
Defeat the Boss [The Coffin Of Pharaoh] on the 30th layer
Defeat the Boss [The Burial Skeleton King] on the 35th layer
Defeat the Boss [Degenerate Archbishop] on the 40th layer
Defeat the Boss [Tauren Warrior] on the 45th layer
Reach the 50th layer of the dungeon
Expand Storage Warehouse to 10 pages
Expand Storage Warehouse to 15 pages
Expand Storage Warehouse to 25 pages
Have more than one hundred thousand gold coins
Have more than one million gold coins
Found 20 kinds of rings
Found 30 kinds of rings
Found 40 kinds of rings
Complete [Adventurer Tutorial]