The Hearts of Stone Add-on for The Witcher 3: Wild Hunt has 12 achievements worth 450 gamerscore.
Be under the influence of seven potions or decoctions at the same time.
Finish the "Hearts of Stone" expansion.
Provoke all Iris von Everec's Nightmares into fighting you at the same time and defeat them.
Recreate all of Iris' nightmares in the Painted World.
Collect all available Ofieri armor and horse gear, and at least one Ofieri sword.
Defeat all the fallen knights and loot their campsites.
Buy all the items put on the block at the Borsodis' Auction House.
Kill 20 cows.
Participate in all the activities at the wedding.
Kill the prince cursed into a toad.
Slide downhill uninterrupted for at least 10 seconds.
Kill 3 opponents with their own arrows.