From Sonic Retro
Chaotix's roots can be traced back to a internal Sega Mega Drive demo, Sonic Crackers, pitching Sonic the Hedgehog and Miles "Tails" Prower joined together by an elastic connection, and must use their combined speed and strength to navigate stages. Crackers (or Sonic Stadium as it was also called) was never publically announced, but the pitch was seemingly accepted and was brought over to the new 32-bit Sega 32X platform.
Following the move, Sonic was turned into Mighty the Armadillo and Tails was removed entirely, and then a series of new characters were added, turning the project into a game about Knuckles the Echidna. Development occurred simultaneously with the 32X hardware, which may explain the need for a colour test screen and a range of (often needless) graphical effects to demonstrate the console.
The "Attractions Information" area is arranged differently, with Speed Slider having a different palette.
Chaos rings name change
Knuckles Chaotix also has six collectible rings called the Chaos Rings, which originally had a different name. They where originally called the "Holy Rings". It seems likely that the ring were renamed in order to avoid any religious controversy.