Here is the full list of all 36 Full Metal Furies achievements.
Complete the game (true end) on NG+
Unlock every piece of equipment for every Class
Unlock every item in the Treasury
See the World
Defeat Titan King Prometheus
Make a choice
Enter the Cave
Solve the Last Puzzle
Solve the Fifth Puzzle
Solve the First Puzzle
Solve the Second Puzzle
Unlock Cerby
Solve the Fourth Puzzle
Solve the Third Puzzle
Find All Monolith Stones in the Stygian Well
Appease Ferryman Charon
Destroy the World
Defeat Planetar Cronus
Find all Monolith Stones in Tartarus
Complete all Class challenges
I always wanted a sibling
Defeat Sky Sniper Lelantos
Find all Monolith Stones in the Desert of Atlantis
Have 1 point in every skill for 1 Class
Air crit an enemy 5 times in a row
Find and translate all Monolith Stones in the Foloi Forest
The synopsis looks grim
Defeat Land Fortress Coeus
Master a piece of equipment by reaching its max level
Defeat Wavebreaker Meneotius
Crack the code for at least 1 Computer
Find and translate all Monolith Stones in Thessaly
Earn 1 level in your equipment
Unlock Go-Cat
Find your first Monolith Stone
Unlock your first piece of equipment