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.
100% Completion + 1%.
Read every Journal Entry.
Collect every Mask.
Collect everything.
Light every beacon.
Say the perfect words in every Relationship.
Complete every Side Quest.
View every Lookout Point.
Collect every Feather.
Conquer every Fortress.
Catch every Fish.
Reforge every Legendary Weapon.
Catch every Herptile.
Visit every Fast Travel location.
Reach Lv 100.
Finish the Main Quest.
Unlock every Skill.
Finish the Completionist Skill Tree.
Finish the Speed-Runner Skill Tree.
Finish the Generalist Skill Tree.