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 stole Jewel
You ground-down Goldo and wrecked Rollie
You have the Arcanium Smelter
You cured Sir William's disease
You and your Mistress have rocked the Dark Tower
You have the Durium Smelter
You have harvested a huge amount of Minions
You put Oberon to Sleep permanently
You have Blue Minions!
You have Green Minions!
You lasted for 30 minutes in Survival
You lasted for 15 minutes in Survival
You lasted for 5 minutes in Survival
You won 50 ranked Slaughter matches
You won 10 ranked Slaughter matches
You won a ranking Slaughter match
You won 50 ranked Pillage matches
You won 10 ranked Pillage matches
You won a ranking Pillage match
You completed a ranked Pillage match
You have a Mistress
You have the Steel Smelter
You have harvested a lot of Minions
You have Red Minions!
You punctured Melvin Underbelly
You completed a ranked Slaughter match
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
Get angry with a Hero
Defeat the 7th Hero
Win with the blackest heart
Win with the clearest conscience
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 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
You lasted for 45 mins in a Expansion Survival Map
You won 25 ranked Expansion Pillage Maps
You won 25 ranked Expansion Slaughter matches
Defeat the 7th Hero in Legendary Mode
You've conquered the Golden Halls Abyss
You've conquered the Evernight Forest Abyss
You've conquered the Heavens Peak Abyss
You've conquered the Mellow Hills Abyss
Defeat all the Expansion Dungeon Creatures
Conquer the Ruborian Desert Abyss