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