In Crosstown, stars of the let's play web series Game Grumps, Arin Hanson and Ross O'Donovan, make a cameo where they can be seen together drawing on pads. Both Ross and Arin also voice characters in the game.

The game's world was originally called Orthodoxia, but this was later changed to Cvstodia.

The collectible 'Sternum of Vitas, the Performer' is a reference to the real-life actor, producer, writer and Did You Know Gaming? contributor Vitas Varnas. The description for the item reads, "Cvstodia remembers with admiration the name of Vitas Varnas. He inspired the lives of his people through his altruistic actions as well as his inspirational words."

Within the game's data are unused graphics for a an ability that would see Kirby shrink down to a small size. Because of their placement in the game's data, it's speculated that this ability was replaced by the UFO power.

In 2002, this game gained controversy after teenagers in San Diego noticed some of the videos involved attractive nurses with syringes, as well as alcoholic drinks, which was seen as promoting drug and alcohol abuse.

Unused graphics in the data suggest this game could have been brought to European countries under the name "Dancing Stage Solo". It is unknown why this version was not released.

Much like in Dance Dance Revolution Solo Bass Mix a unused, more simplistic variant of the banner of "TOGETHER AND FOREVER" by NINEBALL feat. ATOMIC GUN & JULIA can be found in the game's data.

A more simplistic background image for the song "WILD RUSH" can be found in the game's data.

An unused texture of the Felt Friends can be found in the game's data, suggesting they may have been planned for some kind of role in the game.

While battle damage is used for Little Mac in the Wii U version, data suggests that other characters were planned to have similar effects. This can be seen in unused textures for R.O.B. in the game's data which seem to show battle damage. This is a remnant to Super Smash Bros. Brawl in which characters were also planned to have battle damage, but were left out.

In all versions of the game, there's an unused message that reads:

"Buzby sucks eggs, and Eastwood smells!"

According to the game's lead artist 'Jason Wilson', this is meant for one of the game's main programmers 'James Busby' as an inside joke. Later, it was revealed to be true by 'Chris Sorrell' in the RETRO Vol. 8 interview.

Cole, Toro and Kuro all have continue animations for the Arcade Mode in the PlayStation 3 version of the game. Because neither of these characters are playable in this mode, these animations go unused.

Within the game's files is code for a 6th difficulty that goes unused. It would've been called Encore, and "The Disappearance of Hatsune Miku" is the only song that has a fully completed chart for it. Encore would've been the hardest difficulty in the game, as it would've contained it's own unique notes in the form of randomization. Meaning that the notes (Triangle, Square, Circle, and X) would be different each time the song is played. The only exception to this would've been if the player chose to retry the song.

The character Jeffry McWild was modeled after real life martial artist Willie Williams. At some point in development, Jeffry was planned to be named Willie but his name was later changed due to copyright concerns.

There is an unused ending that exists within the game's code. The ending includes an image and text that reads: "Mister Data, set a course for Earth, Warp Factor Seven. Engage. (heh, heh, heh...)" "Man I bet I could really pick up the babes with this thing..." "Drinking all that soda...hmmm, I'm really not looking forward to seeing what Rigelatin bathrooms look like..."

In the international release the character's name Sodom was changed to Katana.

There's data within the game's files for two unused characters, Wovama and Q.Takagi. When hacked into the game, both characters use Cassandra's model and will randomly pick a weapon and moveset. While the model and movesets for both character's were never created, their names do appear on the verses screen. But when used in game, Wovama's name remains blank under her health meter, and Q.Takagi's name will change to Spawn. Because neither character have models, it is speculated that they were cut very early in the game's development.

The training room is completely modeled out in the 3DS version compared to the original release on the GameCube. However, in both cases, the player cannot use the Game Boy Horror, making it impossible to see through normal means.

Typing in "BR&ND@R@CKS" at the password screen in the Game Boy Color version will show off two shoutout images made by a developer: one of his friends and family, and another of his/her dog named Brando.

In the updated rerelease of the game, Wheel of Fortune 2nd Edition, unused categories regarding "Fictional Place," "Place," "Person/Title," "Foreign Word," "Slang," "Proper Names," "Song/Artists," and "Events" can all be found in the PlayStation version's data.