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