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