LicensingThe original creator Tetsuya Mizuguchi had to get the license back from SEGA in order to issue the Xbox 360 version of the game, even though he created the game at the time. That is because video games created for a company are usually considered "work for hire".
Pause MenuAn undocumented feature for the PS2 release of the game is that while you are in the pause menu during gameplay, you can press triangle and square together and the pause menu will disappear allowing you to see the game behind it.
Dreamcast VersionRez was released on the Dreamcast, months before the PlayStation 2 release took place. It's not widely known that it was ever released on the former platform - both SEGA and UGA officially mention the PS2 release only. This is very likely due to the fact that SEGA discontinued the Dreamcast months before the release of Rez. As a result, there was no American release of Rez on the Dreamcast, and there was no real publicity surrounding the European release either, making it a hard-to-find title.
The Dreamcast version is relatively rare today, especially because the game suffered from many defective pressings. The risk of ending up with a non-working copy of the game is therefore something to be considered when prowling eBay or other online auction sites.
Beta SoundtrackOn 2003, July 31st, a private Rez event occurred in Tokyo, where the team showed new game content to a few selected people. One of the levels was based on Fat Boy Slim music, but never made it into the game due to licensing reasons.
A leaked beta version of the game also contains a list of artists whose music was meant to be implemented at that point in development, including Underworld, Aphex Twin, and The Chemical Brothers.
Wassily KandinskyAt the end of the credits, Rez is quoted to be "dedicated to the incredible creative soul of Kandinsky".
Abstract artist and composer Wassily Kandinsky was a synaesthete (a person with the neurological condition in which two or more senses mingle into one), meaning he was able to 'see' music and 'hear' color. He described his works as quoted:
"I applied streaks and blobs of color onto the canvas with a palette knife and I made them sing with all the intensity I could..."
The nature of Rez's audiovisual experience and the references to synaesthetia are obviously linked to Kandinsky, as well as the working title, K-Project.
Trance VibratorThe Japanese Playstation 2 version was also sold as a limited edition box, bundled with the Trance Vibrator - an additional (external) Rumble Pack whose name left little to be desired of the imagination.
1001 Video GamesThe Xbox 360 version of Rez HD appears in the book 1001 Video Games You Must Play Before You Die by General Editor Tony Mott.
MorolianOne of the player forms you can unlock for the "Beyond" levels is simply called "Morolian". This is an alien invader from UGA's previous game, Space Channel 5.
TitleThe game's title comes from the song "Rez" by Underworld.
Scrapped ConceptsRez went through several design concepts during development. At one point, the player avatar was meant to be seated in a large chair with woofer speakers, and the soundtrack was intended to be mainly hip-hop. Another stage during development had the avatar as a less abstract human form who walked on the ground instead of floating. Another proposed aesthetic for the game was based heavily on water and microscopic organisms.
Information also contributed by glidefan, Apogee IV, Bock, Sciere, and FatherJack.