Sega showed off a VR mode for the first-person horror game Alien: Isolation, running on an early version of the Oculus Rift way back in the summer of 2014. It never evolved beyond the prototype stage, but the files that enabled the VR mode were still present in the game when it shipped. They were hidden, however, and more to the point inoperable, thanks to the many changes made to the Oculus SDK between the Development Kit 2 (which the demo ran on) and the release of the consumer version a couple of years later. But thanks to the magic of the MotherVR mod being developed by Zack "Nibre" Fannon, it's working (with some limitations) once again.
Fannon told Road To VR that the old Oculus development kit doesn't rely on external files to operate, but "gets statically compiled directly into the game," and is thus very difficult to modify. "This limitation is the main reason why support has been restricted to the DK2 and older legacy runtimes for so long,” he said. “How I’ve been able to circumvent that is by patching every SDK call in the game when it launches, to redirect it to my own ‘fake’ SDK code. I then take these requests from the game, and reinterpret them to the current Oculus SDK, translating and fixing things along the way.”
Technical issues aside, Fannon said that some of the limitations of the VR mode, including "mandatory smooth turning, head-locked aiming, broken re-centering that doesn’t correctly align the game horizon with the real world horizon (that was terrible before I fixed it), body positioning in VR (objects way too close), [and] forced head animation," simply reflect how the field of VR development has changed over the past few years.
"To be fair to the developers though, in 2014 we really didn’t know as much regarding VR methodologies as we do now. So with that in mind, their VR support was actually pretty good for the time," he said.
He also warned on the MotherVR Github page that Alien: Isolation VR is designed for seated play only. "By playing this Mod any other way than seated, you do so at your own risk. You may be able to stomach this standing, but I absolutely cannot recommend it at this time. Roomscale does not work whatsoever right now."
It's still very early in the process—the currently available version is alpha 0.1.1—but Fannon said he wanted to make the mod available "so people can play with it while I continue to work on it." It only supports the Oculus Rift at the moment, but he hopes to have "basic Vive support" operational soon, and support for VR controllers like the Oculus Touch added at some point in the future.
A video of the Alien: Isolation VR prototype in operation can be seen below.