Like The Huge Adventure, some copies of the game came with a poster.
This was the first game to have different logos between NTSC-U and PAL, different names notwithstanding.
N. Trance's portion of the Hyperspace island is based on Salvador Dalí's painting The Persistence of Memory, with several melting clocks.
The level Wild Nile Ride has a hidden message under the floor before the second Checkpoint. This is impossible to view without the use of a graphical tool, but it is also present in the Official Prima Strategy Guide (see scan submitted by Ntropydude here). The message says "TATTA", followed by the Vicarious Visions logo and a smiley face.
Music
The main theme is, once again, remixed from Crash 3, as is the Warp Room theme.
Island Intro, as well as all the Atlasphere levels, have the exact same music as the jungle levels from The Huge Adventure, which, in turn, was just a rearrangement of the jungle levels from Crash 2.
The Arabia, Egypt and volcano levels borrow their themes from Crash 3, with the volcano levels using the pre-historic swamp music.
References
Now It's Istanbul is a verse from the song Istanbul (Not Constantinople) by They Might Be Giants.
Lagooney Tunes is a reference to the Looney Tunes.
Prints of Persia is a reference to Prince of Persia.
King Too Uncommon is a pun on the name of the Egypt king Tutankamon.
101 Arabian Kites is a reference to the book 1001 Arabian Nights.
Flockfull of Seagulls might be a reference to the music band A Flock of Seagulls.
Mister Lava Lava is a parody of a verse from the song Mr. Bombastic, which goes "Mister lover lover".
Fire Walker might be a reference to the 1986 movie Firewalker.
Rock the Casaba is a reference to the song Rock the Casbah.
