DJ GEMS Demo

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This game was never completed and/or given a public release. As a result of this, keep in mind that the developers might have used or deleted some of the content featured here, had the game actually been released.

This prototype is documented on Hidden Palace.

D.J. GEMS Demo is a Genesis cartridge created in 1994 for departing Sega of America composer David Javelosa, taking Sega's existing GEMS Module Test Program and loading it up with a collection of Javelosa's original GEMS tracks, producing what amounts to a demo tape in cartridge form for the artist.

The demo surfaced publicly in May 2019 when one of Javelosa's game design students recognized the Sonic 2 material during a class demonstration and shared it online, with a recording soon appearing on the artist's YouTube channel. It was later dumped by Ashley Rojas in May 2026 and released the following September.¹

Unused Graphics#

Near the beginning of the ROM is a different 1BPP font than used by the demo. This is actually meant for a region lock mechanism used in a handful of titles, but since all regions are valid for this game, this font goes unused.

Unused Palettes#

An alternative, brighter palette exists for Sonic. It also turns Tails blue.

Unused Music#

This needs some investigation. Discuss ideas and findings on the talk page. Specifically: Why exactly does the song break and how is it fixed?

Track 03 of the Sonic 2 module contains a song titled "Cabaret Scene" which either refuses to play or attempts to play but breaks depending on the console motherboard revision. When fixed, this track is revealed to be a faster version of "Club Scene" with minor edits to the instruments.

References#