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