Here is the full list of all 18 Brainwashing with Tentacles R achievements.
Finish prologue
Brainwash the daughter of weapon shop
Brainwash the feline girl
Brainwash the farm girl
Brainwash the tool shop clerk
Brainwash the elf mother
Brainwash the elf girl
Brainwash the mansion maid
Brainwash the mansion mistress
Brainwash the sister
Brainwash the magician
Brainwash the female warrior
Brainwash the innkeeper's daughter
Brainwash your superior
Rebel against your superior
Hand Lisa over to Levia
Run away from your mission
Get caught by the female warrior