Sonic X-treme was a cancelled
platform video game in the
Sonic the Hedgehog series. Developed by Sega Technical Institute (STI),
X-treme was designed to capitalize on the success of Sega's mascot character by being the first fully
3D Sonic game and the first original
Sonic title developed for the
Sega Saturn. During the course of development, several different styles of gameplay were tried and the plot of the game changed several times.