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