Sonic X-treme began development in late 1994 under the codename "Sonic Mars", and was planned for the Sega 32X as an isometric side-scroller, but eventually became a full 3D game with a view set on a floating plane. Due to this significant change and the commercial failure of the Sega 32X, the original ideas for Sonic Mars were scrapped and reworked into a Sega Saturn game that would eventually became Sonic X-treme. In 2007, two different sets of early design documents were leaked for the Sonic Mars concept. The first, written by the game's first executive producer and team leader Michael Kosaka, focused on the 3D graphics and notably included elements from the 1993 Sonic the Hedgehog television series (referred to by fans as "Sonic SatAM"), which was airing at the time. The second, written by lead programmer Don Goddard, focused more on how the game combined 3D graphics with 2D sprites, and dropped the SatAM elements.