Here is the full list of all 19 Sixth Grade Detective achievements.
Get a makeover.
Get a book on codes and ciphers.
Finish the game without attempting to blackmail anyone.
Find Red Lightning.
Follow the clues to your birthday present.
Accuse the right person of stealing Shashi's books.
Find a bike.
Get some fingerprint powder.
Get a pair of binoculars.
Play Swords and Sorcerors.
Publish an article in the school newspaper.
Help Evan come clean about his makeover business.
Find the source of the mean rumors.
Destroy the mean notebook once and for all.
Figure out the identity of your secret admirer before the dance.
Start a romance.
Start multiple romances at the same time.
Buy your very own bike!
Finish the game without lying.