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