Here is the full list of all 54 Divinity: Original Sin - there are Enhanced Edition achievements worth 1,000 gamerscore.
You've found a silky souvenir.
You've found the legendary teleportation devices of Rivellon
Esmeralda is your primary suspect.
Meet a talking shell called Ishmashell.
Defeat the four elemental demons.
Try to sneak past Junius and Bibius…
Find an unconventional job for the unemployed.
Free Esmeralda from prison.
Defeat Evelyn and find Councillor Jake.
Pass the test! Well, one of many.
Inform Selenia about the source of the undead.
Safely return to the surface.
Save Bonnie!
Make Archibald king of the trolls.
Kill the ghost of Pontius Pirate.
Solve the Mirror Dungeon puzzle.
Arrange a marriage between Sam and Maxine.
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.
Pull the wrong lever in the Pontius Pirate's lever puzzle in the Black Cove.
Totally, completely, and utterly finish the game.
Find a fitting job for the unemployed.
Deliver Blossius' will to Marisa totally unaltered.
Get the Fabulous Five out of town.
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.
Make Zombie Nick do your bidding.
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.