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