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.
Read every Journal Entry.
100% Completion + 1%.
Collect everything.
Complete every Side Quest.
Catch every Fish.
Reforge every Legendary Weapon.
Conquer every Fortress.
Collect every Mask.
Catch every Herptile.
Collect every Feather.
Say the perfect words in every Relationship.
View every Lookout Point.
Reach Lv 100.
Visit every Fast Travel location.
Finish the Speed-Runner Skill Tree.
Unlock every Skill.
Light every beacon.
Finish the Generalist Skill Tree.
Finish the Main Quest.
Finish the Completionist Skill Tree.