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