Here is the full list of all 37 The Caligula Effect: Overdose achievements.
Acquire all achievements.
Complete the main story with both the male and female protagonist.
Complete μ's Character Arc.
Complete Thorn's Character Arc.
Complete Aria's Character Arc.
Exterminate the Go-Home Club.
Solve the mystery of the 21-class leader.
Complete all Ostinato Musicians' Character Arcs.
Solve all Enigmas.
Complete μ's Remnant Episodes.
Clear a melee battle.
Complete all Go-Home Club members' Character Episodes.
Complete Wicked's Character Arc.
Complete Shadow Knife's Character Arc.
Banish Eiji from the Go-Home Club.
Clear the Shogo and Izuru battle.
Complete a person's Character Episode.
Complete Ike-P's Character Arc.
Raise the protagonist's level to higher than 50.
Clear the Kotono and Eiji battle.
Complete Mirei's Character Arc.
Accumulate over 100 friends with ★ Affinity.
Send group WIRE messages over 10 times.
Complete Kuchinashi's Character Arc.
Collect over 300 Stigmas.
Clear the Suzuna and Naruko battle.
Complete Shonen-Doll's Character Arc.
Clear the Mifue and Ayana battle.
Complete Stork's Character Arc.
Accumulate over 100 friends.
Begin activities as part of the Ostinato Musicians.
Complete Sweet-P's Character Arc.
View your field WIRE over 10 times.
Complete Kagi-P's Character Arc.
Begin activities as part of the Go-Home Club.
Experience your first battle.
Answer μ's call.