Here is the full list of all 13 Meowhalla achievements.
You managed to defend your honor against Freya.
You dodged intimate relationship three times in a row.
You managed to die in a visual novel. Good job!
You managed to end the game without killing any of Disir.
You got Erica's ending.
You got Inkeri's ending.
You got Astrid's ending.
You got yourself a slave.
You managed to end the game without the battle against Hel army.
You got Olga's ending.
You actually needed Erica's saliva to save someone.
You got Freya's ending.
You tried to run from Freya. Unsuccessfully.