Here is the full list of all 21 Deep Dark Dungeon achievements.
Be killed by Lichen Lich.
Buy first medal.
Finish the game alone.
Finish the game with 2 players.
Finish the game with more than 3 players.
Collect 30 medals.
Finish the game without medals.
Finish the game without continuing.
Finish a level collecting less than 10 golds.
Finish the game with single weapon.
Destroy a enemy with 20 different weapons.
Be killed in tutorial.
Fry 200 Eggs in dungeon.
Make a minion kill the Lichen Lich.
Defeat Ninja Goblin with a katana.
Defeat Great Lava Worm with a book.
Defeat King of Chess with a musket.
Have 3000 golds by the end of game.
Defeat the Lichen Lich.
Defeat the Goblin Squad.
Defeat the Giant Lava Worm.