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