Here is the full list of all 11 Starlight Vega achievements.
Complete the harem ending
Shared a kiss with the queen of the demon realm
Around the frigid Queen
You chose the dark side. (there's no cookies)
Shared a kiss with a sultry redhead
Ward off Lyria's flirty advances. Or don't.
A not so happy ending. Let's try again!
Shared a kiss with your best friend
Well, she does look pretty amazing.
A sweet and confusing confession.
You did it!