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%.
Reforge every Legendary Weapon.
Collect everything.
Catch every Herptile.
Catch every Fish.
Say the perfect words in every Relationship.
Complete every Side Quest.
Visit every Fast Travel location.
Conquer every Fortress.
Collect every Mask.
View every Lookout Point.
Light every beacon.
Finish the Main Quest.
Collect every Feather.
Reach Lv 100.
Finish the Completionist Skill Tree.
Unlock every Skill.
Finish the Generalist Skill Tree.
Finish the Speed-Runner Skill Tree.