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