Here is the full list of all 18 Alone achievements.
Catch and cook your first fish
Repair your Ship, and Travel
Smelt a Copper Ingot
Obtain your first Orium weapon
Conquer one of the islands
Reach the second level of the Crypt
Reach the fifth level of the Crypt
Build a Temple
Brew your first beer
Unlock Ironworking
Build a house
Build a Jarl's Hall
Destroy 10 undead foes
Having built a cookhouse, mix your first batch of stew
Improve the ship, unlocking the best sails
Succeed in taking a sapling from a world tree
Pet a feline companion
Obtain Noble Clothing