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