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