Full list of all 22 World II: Hunting Boss achievements worth 1,000 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox One.
Defeat Gianyvern
Complete 12 C-Grade missions
Defeat Mizuchi
Dorrit reaches Lv 10
Sean reaches Lv 10
All heroes reach Lv 10
Violet reaches Lv 10
All heroes reach Lv 5
Complete mission 10x
Own 3 Heroes
Defeat Butcher
Complete 5 D-Grade missions
Finish missions and get 5 S-ratings
Defeat Beholder
Defeat Steel Dragon
Defeat Lava Ape
Complete 10 B-Grade missions
Finish missions and get 5 A-ratings
All heroes reach Lv 15
All heroes reach Lv 20
Fail mission 10x
Completion of all achievement