Sometimes information thought lost to the ages shows up when you least expect it.  In this case it's the long-unknown character and gameplay designs for the Sega Saturn's Sonic X-Treme, the 32-bit Sonic the Hedgehog game that after three years of development never saw the light of day.  Limited details about the game have been kicked around online for years, but now one of the game's ex-developers has come forward to share graphics and sample gameplay animations with fans.  Christian Senn (known as kurisu on his website's forums and also known as the man who nearly worked himself to death while developing the game) is offering up character designs, storyboards, sample gameplay segments, and much more from the aborted Sonic X-Treme.

I've received so many emails asking for information, pictures, playable versions, etc. that I just couldn't keep up. This is my way of trying to give back to the community.  A summary for anyone who doesn't know: I spent 3 years pouring my heart, soul, blood, sweat and tears into the game. I started as an artist and worked my way to designing, leading the design and coordinating part of the team. Many problems occurred on the project. I was young, very ambitious and a perfectionist. I was a part of a large team that started small and grew to 30+ people.

After ten years fans finally get to see then-new character Tiara Boobowski, her professor/king father Gazebo, plans for a playable Knuckles, and much more.  However, as GameSetWatch says, watch out for plenty of comments from aspiring young game developers seeking to "finish" and release the defunct game (nevermind that there's nowhere near enough information revealed here to do so and, from what has been learned about the game over the years, there was never enough of the game actually finished to determine just what the final product would have become).  Based on some of the sample gameplay test animations it looks like Sonic X-Treme could have been a fun little game.  It wouldn't have been anywhere near Super Mario 64 in scope, but still fun in an early-3D-era sort of way.