Fire up your Saturn consoles. The Point of View Sonic Xtreme prototype is ready to go.
By this point, if you’ve been hanging around the Sonic Scene for a fair bit of time, you know that unreleased games and prototypes are somewhat of a big deal. From Sonic 1 pre-alpha images, MegaDrive rom dumps of prototypes, and even some newer material with previously thought lost to time assets (see: Hidden Palace and its return to prominence in 2013 and the prototype Windy Valley in Sonic Adventure), it’s not uncommon around here.
So what’s so special about this prototype, released by Sonic Xtreme researcher JollyRoger? In its ill-fated development, Sonic Xtreme went through a lot of changes from a 32X game codenamed Sonic Mars to a Saturn game running on the 3D NiGHTS engine (in reality, a completely separate engine under the name Project Condor), to the more well known trippy fish-eye lens look. However, prior to the game being scrapped entirely, SEGA of America attempted one last ditch effort to realize the project by having the title exported to a company named Point of View.
What resulted is the demo video seen above. Forum user and prominent Sonic Xtreme research guru Andrew75 ascertained how this step may have transpired in the game’s development.

From what I gather, sometime in the middle of Sonic X-treme’s development, Sega outsourced the completion of Sonic X-treme to Point of View studios, without the knowledge of technical lead Ofer Alon or artist Chris Senn, who were working on the PC and Saturn engine and levels.
Point of View used assets from the original effort and developed a level converter to convert Sega Technical Institute’s engine levels into the binary format used by POV’s own engine, which had already been used before for several other games on a variety of
platforms, such as Saturn, Playstation, Nintendo 64, PC.

There is a whole lot more information available in the topic on the forum and through Senn’s website. However, for those of you that can play burned Saturn games (tricky stuff. Don’t try it at home) or have access to play it through certain other means, you can nab the iso right here with mirror links in the topic.