Sonic Saturn (lost build of cancelled Sega Saturn prototype of platformer; mid-1990s)
During the production of Sonic X-Treme, Sega Technical Institute were planning to make another Sonic game for Sega's ill-fated console, the Sega Saturn. The game's work in progress title was "Sonic Saturn". Unlike Sonic X-Treme, the game's world was meant to be more realistic. Based on what very little concept art that has actually been leaked, it (like X-Treme) appeared to have Metal Sonic in it. 
It was never actually announced to the general public, and also didn't get far into production before cancellation.
Sonic Pool[edit | edit source]
Like other Sonic the Hedgehog games, Sonic Saturn was planned to have 3D special stages. (Similar to Sonic 2, Sonic 3 and Knuckles, Sonic 3D Blast, e.t.c.) It had Sonic in a 3D environment playing pool. The objective (like other main-series Sonic games) of the special stages are assumed to be to collect the seven Chaos Emeralds.
Screenshots of the Pool Mini-Game
[ First Image]
[ Second Image]
[ Last Image]