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