Full list of all 54 Overlord achievements worth 1,250 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 44 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 10 achievements worth 250 Gamerscore.
You have Green Minions!
You have Blue Minions!
You have harvested a lot of Minions
You have a Mistress
You have the Steel Smelter
You have Red Minions!
You punctured Melvin Underbelly
You have recovered the Food
You have started rebuilding the Tower
You have harvested a few Minions
You have retrieved the Tower Heart and powered up the Tower
Put a Hero to sleep. Permanently.
Cure a Hero of life
End a Hero's obsession
Steal a Hero
Get angry with a Hero
Defeat the 7th Hero
Win with the blackest heart
Win with the clearest conscience
Retrieve a powerful Smelter
Retrieve the most Powerful Smelter
Forge an Ultimately Imbued Steel Set
Forge an Ultimately Imbued Durium Set
Forge an Ultimately Imbued Arcanium Set
Forge a full Durium set
Forge a full Arcanium set
Harvest a huge amount of Lifeforce
Harvest a massive amount of Lifeforce
Collect all the Tower Objects
Get a full Horde, fully equipped
Defeat half the Dungeon Creatures
Defeat all the Dungeon Creatures
Fulfill your Mistress's wishes
Last for 5 minutes in Survival
Last for 15 minutes in Survival
Last for 30 minutes in Survival
Complete a ranked Pillage match
Win a ranked Pillage match
Win 10 ranked Pillage matches
Win 50 ranked Pillage matches
Complete a ranked Slaughter match
Win a ranked Slaughter match
Win 10 ranked Slaughter matches
Win 50 ranked Slaughter matches
Defeat the 7th Hero in Legendary Mode
Last for 45 mins in a Expansion Survival Map
Win 25 ranked Expansion Pillage Maps
Win 25 ranked Expansion Slaughter matches
Defeat all the Expansion Dungeon Creatures
Conquer the Mellow Hills Abyss
Conquer the Evernight Forest Abyss
Conquer the Heavens Peak Abyss
Conquer the Golden Halls Abyss
Conquer the Ruborian Desert Abyss