Here is the full list of all 33 Cosmic Star Heroine achievements.
Defeat the Prime Evil
Defeat a special bounty
Reclaim your high score
Gain at least 20 recruits for your ship
Defeat the ultimate zombie
Scare rats away in Gehenna
Share a soda
Win first battle in game on hardest difficulty level
Complete the game
A party member betrays you
Defeat a true hero
Find the ultimate ingredient
Defeat a cosmic entity
Gain Chahn's ultimate ability
Gain your final party member
Prove your innocence
Defeat the Crystal Wraith
Defeat the Nightmare
Deal over 9999 damage in a single hit
Escape confinement
Use Clarke's Self-Destruct ability
Win a VR Battle
Chat with your party members
Commandeer your own spaceship
Use a Heroine program
Defeat the Blobmith
Win every round of Rock Paper Scissors
Reach Lauren's apartment
Charm an enemy
Reach 300 Style
Defeat Spectral Dragon
Defeat the lab guardian
Complete SkyBreaker Tower scenario