Here is the full list of all 49 Mighty Dungeons achievements.
Kill 100 monsters
Kill 50 Goblins
Drink more than 100 potions
Drink more than 300 potions
Drink more than 500 potions
Kill 300 monsters
Kill 500 monsters
Complete the Skeltor Campaign
Open 200 doors
Open 400 doors
Open 600 doors
Kill 50 Skeletons
Collect 20000 gold coins
Complete the Forbidden Dungeons campaign
Kill 1 Crystal Golem
Use a short bow more than 500 times
Kill 20 Hell Hounds
Kill 50 Warriors
Jump over 30 traps
Jump over 50 traps
Jump over 100 traps
Disarm over 20 traps
Disarm over 50 traps
Disarm over 100 traps
Complete the Abaddon campaign
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 200 objects
Inspect more than 400 objects
Inspect more than 800 objects
Kill 80 Hell Goblins
Collect 50000 gold coins
Complete the Chaos Gods Campaign
Kill 1 Mithril Golem
Complete the Origins campaign
Collect 100,000 gold coins
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