One of Sega’s most mysterious products ever, the canceled Sega VR headset, finally appeared in a “playable” form on Friday thanks to a team of game history preservers. It’s a tale of a discovered ROM, a search for the source code, and efforts to not only rebuild the game, but also customize existing Genesis and Mega Drive emulators to translate virtual reality calls from today’s PC headsets.
The story, as published on the Video Game History Foundation’s website, begins with a ROM discovery by Dylan Mansfield of Gaming Alexandria. The game in question, Nuclear Rush, was one of four games announced for Sega VR, a headset system designed to connect standard Genesis and Mega Drive consoles.
Not quite 72Hz …
Players from that era have probably heard of Sega VR, as the game publisher’s PR push contained plenty of mentions in gaming magazines, a public revelation at the 1993 Summer CES, and even a segment on ABC’s Nightline. But the ambitious device, scheduled to start at just $ 199, was quietly canceled, and former Sega president Tom Kalinske eventually confirmed why: Researchers found that the device made a huge percentage of testers sick of headaches and dizziness.
Today’s discovery partly explains where these disease symptoms are likely to originate. By breaking down and understanding the way Sega VR games communicated with a Genesis and therefore a Sega VR headset, VGHF’s digital preserver Rich Whitehouse discovered the serious limitations of the headset: only 15Hz update to its stereoscopic images as opposed to the 72Hz minimum for Oculus Quest (let alone the 90Hz standard created by companies like HTC and Valve). In addition, Sega VR only translated pitch and yaw motion for users’ heads, not for scrolling – and this is on top of the system, which is already limited as a three-degree freedom system (3DOF), which requires users to stay seated .
How did Whitehouse find out so much about Sega VR’s functionality many years after the addition disappeared? As it turns out, Mansfield’s daily search for game history bugs includes requests to various 90s developers for the old prototypes or code they may have stored in a drawer. In the case of Kenneth Hurley, who worked on Nuclear Rush as part of Futurescape Productions, he went a higher level and sent Mansfield a CD-ROM dated August 6, 1994 – which miraculously had not bowed to rot.
Whitehouse stepped in at this point to figure out how to compile the remaining almost complete code (called “final” but not “retail final”), which required a mix of C and assembly. Among Whitehouse’s discoveries: the code as written only worked on certain Genesis and Mega Drive hardware versions based on how it handles horizontal and vertical scrolling of sprites and assets, which required a minor fix. Also, metadata in the code suggested a winter CES 1994 that showed for Sega VR that never got past.
Could have used an SVP
Although the detected CD-ROM was missing important Sega VR files (which Whitehouse says would have been named VR.DOC and VR.TXT), Whitehouse was still able to figure out how the system would have worked with 16-bit consoles . Sega VR IO would have been about the console’s second controller port – although Whitehouse’s explanation does not specify whether the console’s video-out port would have been redirected to the Sega VR headset or how it would have worked. In addition, the Sega VR headset would have got two 30Hz images, which Nuclear Rush would then have shared further with its 15 fps update.
While figuring out how to make Nuclear Rush worked as a VR experience in 2020, Whitehouse spoke with the game’s original lead programmer, Kevin McGrath, who confirmed that his team did a lot of work on Sega VR without actually having a headset to test on – and they invented a test that had the game’s video output flickers between two computer screens to see how it can do the same thing with two headset images. Another Sega VR-era game programmer, Alex Smith, confirmed that the team working at Outlaw Racing never even went hand in hand with a headset prototype before the project was canned.
The rest of Whitehouse’s work revolved around building OpenVR support in a working Genesis emulator, which included making serious guesses about how Sega VR’s panels were placed and shaped, and then fixing 1994-era quirks to run more efficiently on modern computers (partly to reduce potential driving sickness from a Genesis-era game locked at 15 fps). The resulting emulator and a few compiled Nuclear Rush ROMs are available for download and testing from the VGHF article.
Ars Technica has tested this combination of emulator and ROM on a Windows 10 PC running an HP Reverb G2 headset, and I can confirm that the game plays as well as you might expect: it’s a rudimentary 3D tank game that about Atari’s arcade classic Battlezone had been rebuilt with Genesis-era sprites and palettes, but it’s all sprite-field trickery, not the rudimentary polygonal things of the early ’90s that Star Fox or Virtua Fighter. (Sega VR games were clearly not bundled with extra cartridge chips like Sega’s SVP used in the Genesis version of Virtua Racing.)
The resulting restored game is not a revolutionary gaming experience by any means. Still, the combined efforts of everyone mentioned above brought life back to a game whose original version would probably have made you sick. Fortunately, modern hardware (and its enterprising users) can revive canceled games in ways that do not make game historians toss their cookies, and this is proof of the modern game preservation movement as a whole.
See the whole exciting story complete with a ridiculous amount of technical information at the Video Game History Foundation.