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.
Complete every Side Quest.
Conquer every Fortress.
Collect every Mask.
Catch every Herptile.
Collect every Feather.
Catch every Fish.
Say the perfect words in every Relationship.
View every Lookout Point.
Finish the Main Quest.
Light every beacon.
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.