Here is the full list of all 54 Divinity: Original Sin - there are Enhanced Edition achievements worth 1,000 gamerscore.
You defeated Evelyn and found Councillor Jake.
You defeated the four elemental demons.
Sam and Maxine are going to be wed!
The Fabulous Five have left town.
You killed the ghost of Pontius Pirate.
Zombie Nick will now do your bidding.
Pulled the wrong lever in the Pontius Pirate's lever puzzle in the Black Cove.
You found a job for the unemployed with the Fabulous Five!
You passed the test! Well, one of many.
You have solved the Mirror Dungeon puzzle.
You found a job for the unemployed. They will work for Captain Jack.
You've found a silky souvenir.
Esmeralda is your primary suspect.
You've found the legendary teleportation devices of Rivellon
You met a talking shell called Ishmashell.
You tried to sneak past Junius and Bibius... And failed!
Free Esmeralda from prison.
Inform Selenia about the source of the undead.
Safely return to the surface.
Save Bonnie!
Make Archibald king of the trolls.
Brew a fine whisky for Hershel.
Find the White Witch!
Meet Leandra in Hiberheim.
Release the elements from Boreas' staff.
Save the Homestead on the Shelter Plane at the End of Time.
Find a way to open the barrier without harming any mushrooms.
Talk to Icara to learn more about her sister's plans.
Decide Arhu is better off human.
Kill Cassandra to get hold of the soul forge repair ritual.
Safely enter Phantom Forest.
Find Zandalor.
Help Jahan face his demons.
Make it into Hunter's Edge.
Solve Bellegar's maze.
Enter the Source Temple.
Finish the Trial of Ascension.
Meet the legendary weresheep!
Come face-to-face with Mangoth himself.
Create a spell that makes Death Knights vulnerable.
Totally, completely, and utterly finish the game.
Deliver Blossius' will to Marisa totally unaltered.
Keep the Tenebrium for yourself.
Make Brandon tell you the truth about the mining guild.
Finish the game in Honour Mode.
Finish the game in Tactician Mode.
Forge the sisters' souls.
Enter the Gnik Barc Nni.
Learn all the skills within one skill tree.
Finish the game with the Lone Wolf trait.
Make Arhu a cat forever
Give Wolgraff his voice back.
Help Bairdotr find Jareth.
Teach Madora the value of mercy.