Here is the full list of all 97 Slay the Princess achievements.
Slay the Princess, and make some enemies along the way
Bring the Wounded Wild to Her
Slay your better
Bring the Apotheosis to Her
Witness your better's ascension
It was in your nature
Directly attack a suspicious character
Kiss her
Bring the Spectre to Her
Pick up a passenger and take her to her destination
There are worse fates to suffer than a broken heart
Take on a spirit and destroy it the only way you can.
Bring the Razor's heart to Her
Allow a sharp foe to vanquish herself
Bring the Prisoner to Her
Become your own jailer
Bring the Drowned Grey to Her
Drown at the hands of a faded spirit.
Have a voice ruin your happy ending
Dispatch a prisoner
Fall for the rest of your life
Successfully take the fight to a creature in its den
Strike the heart from the belly of the beast
Freeze in front of a creature on your first meeting
Fight your foe unarmed and go the distance
Bring the Eye of the Needle to Her
Lure an enemy to advantageous terrain and win
Free someone who doesn't want to be freed
Take the bait from your foe
Bring the Fury to Her
Unleash the power of pacifism on your foe
Bring the Adversary to Her
Cannot die cannot die cannot die
We Carve Meaning
So have you become nothing once again
There's no going back now
This is it
You don't know what you're doing
What can I do to make you stop?
Why have you come back?!
Return to your destined path, or face the consequences
When taken against your will, witness your enemy's freedom
Bring the Wraith to Her
When taken against your will, deal with your enemy the only way you can.
Stuck in a dream without a stair to be seen
Work through some issues and learn to trust again.
Bring the Thorn to Her
Share a thorny prison
Abandon her in a thorny prison
Hand your power to a suspicious character.
Bring the Prisoner's head to Her
Free a prisoner
Bring the Burned Grey to Her
Burn at the hands of a faded spirit
Slay an innocent
Bring the Den to Her
Successfully flee from a creature in its den
Dodge a creature until you can dodge no longer
Bring the Networked Wild to Her
Embrace your transformation
Bring the Beast to Her
Free a creature while under extreme duress
Fool a predator by faking your own death
Bring the Razor (Full) to Her
Master yourself and vanquish a sharp foe.
You did it! You saved everyone!
Bring the Nightmare to Her
Let your terrors loose upon the world
Only new beginnings
Break the mirror without asking any questions.
Some tears can never be mended
Leave a suspicious character in the basement
Slay the Princess
And at the end of that path is a cabin
Finish the Game. (The Good Ending doesn't count)
Whatever it is, you'll face it together.
Beget Strange Endings
Bring the Witch to Her
All of this is you
Run out of questions
It was in her nature
Bring the Moment of Clarity to Her
You've unraveled
See what hides behind her mask
Bring the Damsel to Her
Bring the Tower to Her
Your love will set you free
You've withered
Pledge your loyalty to your better.
Bring the Deconstructed Damsel to Her
You've grown
It's all she wanted
You'll know it when you see it.
Bring the Stranger to Her
Attempt to Out-Wait Your Destiny.
It's you
When everything is possible, nothing is.