From Wikipedia:
A disc of a test engine of X-treme exists. A copy was sold at auction to an anonymous collector in September 2005, and a high-quality gameplay video was expected to be released by the end of the year. An animated GIF image of the gameplay was released to the community. The disk image was finally leaked in July 17, 2007; the README was signed by a certain "Home of the obscure".[2]
In early January 2006, Chris Senn opened a forum based on the game on his own message board, and began revealing large amounts of the game's development history to the public, including videos of early attempts, a playable Tiara, concept art of Tiara, and more. Furthermore, he posted a large amount of previously unreleased concept music related to the title, and was given permission by Hirokazu Yasuhara (the level designer for the majority of the original 16-bit Sonic titles, including the first one) to post level designs that were going to be put in the game. Most of this information is to be posted on the Sonic X-treme Compendium (SXC), which officially went online April 5, 2006
[edit] Project S
Senn later started Project S, an effort to complete the game unofficially. However, he later stated that it will be an original fangame heavily inspired by Sonic X-treme, rather than a straight resuming of the unfinished project. As of July 2007, Project S is currently under development.[3] At one point, there was an article on GameSpot referring to a possible release of a "Project S" for the PSP; however, the released game turned out to be Sonic Rivals.
