Here is the full list of all 46 Deep Dungeons of Doom achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Die in a single hit with full health
Reach the floor 666 on DDD
Reach the floor 300 on DDD
Reach the floor 360 on DDD
Find 10 secrets
Drink poison and die
Kill 1000 monsters
Find 6 secrets
Use a revenge bonus
Find 3 secrets
Buy all Mercenary skills
Buy all Crusader skills
Buy a level 6 skill with the Crusader
Buy a level 6 skill with the Mercenary
Buy all Witch skills
Collect 10000 gold
Slay the Icy Caves' boss while carrying no equipment
Kill 50 beast monsters
Reach the floor 260 on DDD
Reach the floor 200 on DDD
Reach the floor 160 on DDD
Reach the floor 100 on DDD
Reach the floor 60 on DDD
Causing more than 100 points of damage in one hit
Reach the floor 30 on DDD
Reach the floor 10 on DDD
Use a revive
Die on a dungeon first floor
Die for the first time
Buy a level 6 skill with the Witch
Completing a dungeon with 1 hp
Clear the Deepest Dungeons of Doom
Kill 50 undead monsters
Kill 50 human monsters
Find one secret
Kill 100 monsters
Clear 6 dungeons
Clear 3 dungeons
Collect 1000 gold
Collect 5000 gold
Taking more than 20 points of damage in one fight
Kill a zombie
Clear the Sewer
Completing a dungeon without using any potions
Collect 300 gold
Collect 500 gold