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