Here is the full list of all 12 Curse of the Old Gods achievements.
Save the world from the Old Gods.
The Coin wasn't strong enough to close the Portal.
You tried to save the world with empty hands.
You've found a nice hot cup of tea.
You've reached the maximum score.
You've found evidence that the nightwatchman was murdered.
You've tried to eat the giant lunch.
You've saved Miguel's life.
You've tried to shoot Clayton in the face.
You've puzzled the pieces of paper together.
You've wished for a walkthrough.
You've found the connection to the Illuminati.