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