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