Here is the full list of all 12 Exodus Borealis achievements.
Survive the first night on the island.
Defeat a Boss Demon.
Defeat a Boss Hell Spider.
Defeat a Boss Minotaur.
Defeat a Boss Troll.
Defeat a Boss Oger.
Defeat a Boss Golem.
Defeat a Boss Demon Dog.
Defeat a Boss Devil.
Grow a large population of mature trees.
Prepare enough feasts for the entire colony.
Defeat a Boss Dragon.