In Lungfishopolis, if you go to the island with the highest skyscrapers and climb onto one of the buildings closest to the mountain range, angling the camera enough will reveal a grainy picture placed just out of bounds of an Asian woman. At the time of the game's development, this person was world designer Fred Selker's girlfriend.

During the fight with the phantom in Gloria's Theatre, words will appear on screen, such as strained, vulgar and witless. These words were added by Dion Hopkins, who worked on visual effects for the game. He stated that these words were taken from reviews for the 2004 comedy film "White Chicks".

Early in development, the main character was going to be an ostrich with multiple personality disorder. The different powers that the player could use would relate to the different personalities of the ostrich.

There are several sound files for Milla's Dance Party that went unused. Some of these include audio for the sequence in which Milla Spoiler:watches the orphanage she worked at burn down with the children she cared for inside. While there has been no official statement as to why this audio was cut, it's reasonable to assume that it was removed for its disturbing nature.

Psychonauts was originally intended to be an Xbox exclusive at the request of Ed Fries, then vice president of game publishing at Microsoft, to give the console's library an artistic flair. When Ed left Microsoft in 2004, however, the company lost interest and the game went multi-platform.

Raz started development as a small, blue boy named D'Artagnan, but was ultimately redone after the development team had trouble animating his hat. He did, however, make a very brief cameo appearance in the game's ending where he can be seen hiding in an outhouse.

Using Clairvoyance on The Phantom Spoiler:in Gloria's Theater, players can get an early hint as to the fact that the saboteur is Jasper. Both Jasper and The Phantom see Raz as one and a half stars.

Raz, the main character of Psychonauts, is one of two characters in the game who has five fingers on each hand whilst all other characters in the game have only four (the other is his father, Augustus).

Psychonauts only managed to sell fewer then 90,000 copies on the PlayStation 2, Xbox and PC combined in its first year, despite being acclaimed by gamers and critics.