Here is the full list of all 38 Psychonauts trophies - there are 21 bronze, 12 silver, 4 gold and 1 platinum.
Unlock all trophies.
Buy an item from the Camp Store on Christmas.
Complete Meat Circus.
Revisit all brains after completion.
Achieve Rank 101.
Sort all Emotional Baggage.
Gather all Figments.
Crack all Vaults.
Introduce all Camp Kids to Mr. Pokeylope.
Re-brain the Children.
Complete The Asylum.
Complete Gloria's Theater.
Complete Waterloo World.
Find all Golden Helmets.
Complete Black Velvetopia.
Earn all Merit Badges.
Find Edgar's Secret Garden.
Achieve Rank 80.
Redeem all 16 Scavenger Hunt Items.
Complete The Milkman Conspiracy.
See yourself through the eyes of many others.
Complete Lungfishopolis.
Achieve Rank 60.
Cook and consume two different kinds of roast in one sitting.
Spy on Bobby's love life.
Hear Vernon's Ghost Story.
Complete Milla's Dance Party.
Uncover Milla's Secret.
Achieve Rank 40.
Witness Maloof's transformation.
Complete Sasha's Shooting Gallery.
Use the bacon. A lot.
Achieve Rank 20.
Give the Coach's speech on the stump.
Discover the secret history of Whispering Rock.
Read many bulletin board messages.
Complete Basic Braining.
Complete the Punchy Target mini-game.