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