Former Sega Technical Institute dev shares Jester, Segapede and Treasure Tails

Ken Rose, a former senior programmer at Sega Technical Institute (STI), has handed The Hidden Palace a set of floppy disks from his personal collection. They hold design documents, screenshots and, in some cases, source code for Mega Drive games that were never released. The release, themed around Halloween 2026, was picked up by Time Extension on November 3.

Among the highlights is Jester, a clay-figure platformer once touted as a flagship for 1994 and shelved after lead programmer Mark Cerny left Sega. A playable prototype dated February 12, 1993 survives, with mechanics not seen before. Segapede is a Sonic spin-off in which you control one of Dr. Robotnik's mechanical hybrids, renamed Astropede before it was cancelled: a January 25, 1994 prototype and its source code are available. Treasure Tails, an isometric puzzle-adventure starring Tails made for the 1993 holidays, comes with an April 6, 1993 prototype, code and design documents.

Also in the haul: Kid Chameleon, B-Bomb and Dark Empires

The batch includes a Kid Chameleon "Prototype B" that differs from the known December 1991 build, a playable B-Bomb prototype from October 2, 1992, and the source code of Dark Empires, whose May 1992 build matches the previously known prototype. The latter does not compile because assets are missing. For Segapede, developer vladikcomper prepared a slightly modified GitHub repository to make it easier to build.

Each game has its own Hidden Palace page with prototype and sources: see for instance those for Jester and Treasure Tails, as well as the full write-up of the donation. These archives show how much preservation depends on former developers who kept their floppies. The games remain the property of their rights holders: browsing happens on the preservation site.

Source: Time Extension