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