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