Here is the full list of all 54 Divinity: Original Sin - there are Enhanced Edition achievements worth 1,000 gamerscore.
You finished the game in Honour Mode.
You've taught Madora the value of mercy.
You safely returned to the surface after the collapse of the mines.
You have totally, completely, and utterly finished the game.
You finished the game in Tactician mode.
You finished the game with the Lone Wolf trait.
You forged Icara and Leandra's souls.
You have entered the Gnik Barc Nni.
You have found Zandalor.
You have finished the Trial of Ascension.
You have made it into the Source Temple.
You have met the legendary weresheep!
Arhu is a cat forever! If you ever have a problem with mice, you know who to call.
You have killed Cassandra to get hold of the soul forge repair ritual.
You've given Wolgraff his voice back.
You locked up Arhu and forced him to become human.
You have created a spell that makes Death Knights vulnerable.
You have solved Bellegar's maze.
You helped Jahan face his demons.
You have safely entered Phantom Forest.
You brewed a fine whisky for Hershel.
You made it into Hunter's Edge.
You made Archibald king of the trolls.
You have learned all the skills within one skill tree.
You talked to Icara and learned more about Leandra's plans.
You have saved the Homestead on the Shelter Plane at the End of Time.
You came face-to-face with Mangoth himself.
Brandon told you the truth about the mining guild.
You kept the Tenebrium for yourself.
You helped Bairdotr deal with Jareth.
You have found the White Witch!
You have released the elements from Boreas' staff.
You have met Leandra in Hiberheim.
You delivered Blossius' will to Marisa totally unaltered.
You saved Bonnie!
You found a way to open the barrier without harming any mushrooms.
You informed Selenia about the source of the undead.
You freed Esmeralda from prison.
You defeated the four elemental demons.
You defeated Evelyn and found Councillor Jake.
Zombie Nick will now do your bidding.
Sam and Maxine are going to be wed!
You killed the ghost of Pontius Pirate.
Pulled the wrong lever in the Pontius Pirate's lever puzzle in the Black Cove.
The Fabulous Five have left town.
You have solved the Mirror Dungeon puzzle.
You passed the test! Well, one of many.
You found a job for the unemployed with the Fabulous Five!
You found a job for the unemployed. They will work for Captain Jack.
You've found a silky souvenir.
You tried to sneak past Junius and Bibius... And failed!
You met a talking shell called Ishmashell.
You've found the legendary teleportation devices of Rivellon
Esmeralda is your primary suspect.