Sonic Mars was being developed by Sega Technical Institute (STI), a U.S.-based developer that had worked on games such as Sonic 2, Sonic 3 , Sonic Spinball, The Ooze and Comix Zone. In its earliest conception, the game was set to be released on the Sega Genesis and later on the 32X, under the name Sonic Mars (based on the codename for the 32X, Sega Mars). Sonic Mars would also have featured Sally Acorn and the other Freedom Fighters from the Saturday morning animated series, Sonic the Hedgehog. Part of the project staff included Chris Senn, who designed demo animations in order to persuade executives, and Michael Kosaka, who was the staff leader and the game’s producer.
However, that project was eventually shifted: it was decided that the game would require much more powerful hardware to cope with the new engine, and for commercial reasons, Kosaka’s departure from Sega and the eventual commercial failure of the 32X, the release of a Sonic game on the upcoming Sega Saturn console was necessary. [Info from Wikipedia]
You can download the original script for Sonic Mars @ Sonic-Cult