Video game preservation got a Halloween treat. Hidden Palace and DevStash have published playable prototypes, source code, and design documents spanning six Sega Technical Institute projects, all recovered from the floppy disks of Ken Rose, a senior programmer Mark Cerny hired in June 1991. Most of the material had never been seen before.
Rose spent three years at STI working on a string of projects that were cancelled one after another; Sonic Spinball, for which he programmed the bonus rounds, was the only one to reach store shelves. After a December 2025 interview with DevStash founder Ashley Rojas, he dug through his old disks and sent over builds and source code covering 1990 to 1994.
An especially exciting find is Jester, later known as Kinetix, a Cerny-era platformer starring a malleable clay hero, planned as an April 1994 flagship before it was cancelled. Rose’s disks hold a playable April 1991 build with mechanics nobody had seen, including a ball form and tubes. Then there is Treasure Tails, an isometric Tails puzzle-adventure cancelled in April 1993 after the art workload was tallied at roughly four years; its April 1993 build, source code, and design documents are included. Rounding out the haul: a January 1994 Segapede prototype plus source, a genuinely playable July 1992 build of the Joust-like B-Bomb, Dark Empires source code, and an unusual Kid Chameleon prototype.
Rose was let go on February 2, 1994, the day Sonic 3 came out, which is a grim bit of timing. Thirty years of Sega history sat in one programmer’s drawer, and we are very glad he kept it. The haul caps a strong run for preservation, from the over 100 lost Sega Genesis ROMs recovered by the VGHF to a Saturn prototype of a completely unknown cancelled game.
Source: Hidden Palace
