Full list of all 20 Open World Game: the Open World Game achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Read every Journal Entry.
100% Completion + 1%.
Collect everything.
Collect every Mask.
Collect every Feather.
Catch every Herptile.
Reforge every Legendary Weapon.
Conquer every Fortress.
Catch every Fish.
Say the perfect words in every Relationship.
View every Lookout Point.
Light every beacon.
Complete every Side Quest.
Reach Lv 100.
Finish the Main Quest.
Visit every Fast Travel location.
Finish the Speed-Runner Skill Tree.
Unlock every Skill.
Finish the Completionist Skill Tree.
Finish the Generalist Skill Tree.