Alongside the production of Sonic X-treme, STI was working on another game only known as "Sonic Saturn". Rather than use sprites for sonic, though, it was going to use a 3D model for Sonic. This game was meant to have a more realistic rendition of Sonic's world than X-treme. It was never actually announced publicly that it was in production, but didn't get very far before being canceled.
Power Drift is an arcade racer. There are 5 tracks to choose from, each with 5 stages. The stages range from cities, to deserts to tracks over water. There are also 12 drivers to pick from, from businessmen to skinheads and mohicans.
Fantasy Zone is an arcade style shooter for one or two players. The goal is to destroy all of the creatures on each planet and collect as many of the lost coins as possible. At the end of each level is a large enemy that will have to be defeated before moving on to the next world. At various points in the game, the player will be able to find a parts shop, which allows purchasing improvements for his spaceship, including better weapons and faster engines.
Sega Ages Rouka ni Ichidant-R is a compilation released under the "Sega Ages" line for the Sega Saturn. It includes a port of Puzzle & Action: Ichidant-R and Quiz Rouka ni Tattenasai!. It was released exclusively in Japan in 1996.
Gakkou no Kaidan is a game for the Sega Saturn console. It was released in 1995 to accompany the live-action movie Gakkou no Kaidan. It was available only in Japan, in Japanese.