Here is the full list of all 43 The Academy: The First Riddle achievements.
Solve all the puzzles
Take pictures of all blue birds
Re-watch the movie about the baron
Take pictures of all the statues
Solve 50 puzzles
Take pictures of all the butterflies
Finish the final exam
Save professor Wilson
Solve all the paper puzzles
Find the hidden safe
Attend Self-defense class
Attend the Writing class
Find 30 hints
Take pictures of all your colleagues
Solve 15 puzzles
Get 5 wrong answers in class
Play 3 arcade games
Solve 5 puzzles
Attend photography class
Take a bath 3 days in a row
Finish 10 sidequests
Attend the First Aid class
Solve 3 paper puzzles
Get 5 right answers in class
Take 3 pictures with the camera
Find 10 hints
Solve a puzzle in less than a minute
Attend the Painting class
Take a bath
Flush the toilet and wash your hands afterwards!
Make time for a study session
Finish the entrance exam
Talk to every classmate
Make time for a study session every day
Finish the game using no hints
Finish the game using less than 20 hints
Find 100 hints
Solve 7 library book puzzles
Solve every book puzzle
Take a picture of a pinecone on a tree
Find the sculpture
Find the device
Take pictures of all the graffiti