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