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