Here is the full list of all 12 At Your Feet achievements.
Unlock Natalie's Pianist Ending
Unlock Lucy's Conformist Ending
Unlock Victoria's College Ending
Unlock Natalie's Revenge Piano CG
Unlock Lucy's Maverick Ending
Unlock Lucy's Truth Or Dare CG
Unlock Victoria's Athletic Ending
Unlock Melanie's CG
Unlock Natalie's Teacher Ending
Unlock both Victoria's endings with a score of 100
Unlock both Lucy's endings with a score of 100
Unlock both Natalie's endings with a score of 100