Here is the full list of all 18 Symbiotic Love - there are Yuri Visual Novel achievements.
Witness the death of your beloved
Meeting the princess for the first(?) time
First intimate contact
Getting owned at cooking class
Knight comes to the rescue
A small wish comes true
She nearly had her way
Enjoy the live performance
A secret love affair
Girls just wanna have fun
Enjoy the show
The moment I became you
When I become the protagonist
I'll be waiting for you
A body with two souls
When the story becomes true
Let her be never forgotten
Obsession breeds tragedy