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