Here is the full list of all 49 Mighty Dungeons achievements.
Complete the Chaos Gods Campaign
Open 400 doors
Jump over 30 traps
Kill 50 Warriors
Disarm over 20 traps
Complete the Abaddon campaign
Collect 100,000 gold coins
Inspect more than 400 objects
Kill 500 monsters
Complete the Forbidden Dungeons campaign
Open 200 doors
Kill 20 Hell Hounds
Collect 50000 gold coins
Inspect more than 200 objects
Kill 300 monsters
Kill 50 Skeletons
Complete the Skeltor Campaign
Collect 20000 gold coins
Kill 50 Goblins
Kill 100 monsters
Drink more than 100 potions
Drink more than 300 potions
Drink more than 500 potions
Open 600 doors
Kill 1 Crystal Golem
Use a short bow more than 500 times
Jump over 50 traps
Jump over 100 traps
Disarm over 50 traps
Disarm over 100 traps
Cast more than 100 spells
Cast more than 300 spells
Cast more than 500 spells
Cast more than 1000 spells
Resurrect more than 10 times
Resurrect more than 30 times
Resurrect more than 50 times
Use a long sword more than 500 times
Inspect more than 800 objects
Kill 80 Hell Goblins
Kill 1 Mithril Golem
Complete the Origins campaign
Use your weapons more than 5,000 times
Use your weapons more than 7,000 times
Use your weapons more than 10,000 times
Complete the Gates of Hell Campaign
Collect 500,000 gold coins
Complete the Goblin King Campaign
Complete the Black Sheep quests