Galaxy Fortress Zone is a scrapped zone that would have appeared in the Sega Saturn cancelled video game, Sonic X-treme. It is the fifth zone in the game, and was intended to be a part of Death Egg Zone. It is the only zone that was shown at the E3 trailer, along with a variant of Jade Gully Zone.
Much of Galaxy Fortress Zone is unknown, along with most of Sonic X-treme, but it is known that this stage was a space-themed level that marks a similar appearance to the Death Egg Zone from Sonic & Knuckles. Chris Senn stated that this zone is space station scaffolding surrounding the Death Egg. Only one screenshot has been revealed of this stage where it appears that Sonic the Hedgehog could walk on moving platforms to get through the stage.
- Since it's a level from the E3 trailer, it's possible that this level was found along with other v40 levels and will may be released at the future.