Here is the full list of all 50 Lust Theory - there are Season 1 achievements.
Made Zoe cry
Acquired all the other achievements
Ignored Ellie
Used the Gallery
Finished the "perfect" day
Finished the "NFG day" 3
Finished the "NFG day" 4
Blackmailed Nicole twice
Smashed the clock
Finished the "NFG day" 2
Hit Taylor with the ball
Finished the "NFG day" 1
Spied on Zoe playing
Spied on Megan changing
Spied on Zoe in the girl's locker
Found the secret photos on Nicole's phone
Walked home with Zoe after school
Clicked on Zoe's house enough times
Used a certain little red button
Used the Hints button in free roam
Used the fast-forward button to reset the day
Finshed the intro with Nadia
Names all the relationships
Checked out the "About" screen in the menu
Used the "Panic button" once
Sat through the whole main menu video
Used the "Angle button" once
Chose all the correct answers on the pop quiz
Found all 4 interactions before Elizabeth came home
Clicked on the "Whatever" poster
Ratted Jessica out about her date
Tried going into Megan's room at night
Got to "Free roam mode"
Asked Ellie to **** ****
Told Ellie you like trains
Blocked the ball
Told Nicole the truth about Ellie's gun
Barged into Megan's room
Told nicole not to assume your gender
Got impaled by Jessica's heel
Finished the main story
Found EVERYTHING
Was left naked in the School hallway
Finished "Freeze day"
Got enough experience for Ellie's game
Found out about cellulite from Elizabeth
Spied on Megan showering
Reset the day with all the girl's stories active
Touched Sophie without asking
Experienced the first "Lust Time"