For years, the N64's Disc Drive acted as The Great White Hope for Nintendo's third home console. As someone who followed the Console Wars intensely as they unfolded during the mid-to-late '90s, this peripheral was perpetually juuust around the corner, ready to deliver on Nintendo's wild promises.
Unfortunately, the 64DD never experienced the fruitful life Nintendo had in mind for this plucky little piece of hardware. It only released in Japan just a month before the year 2000 struck, and brought with it a meager collection of games that didn't garner a whole lot of excitement. (Sorry, Doshin the Giant fans.) The platform's lack of viability inevitably caused some games to see their development shifted to newer Nintendo hardware, or to have their Disc Drive-specific functions eliminated entirely.
One of the most famous cases of a game surviving the 64DD's downfall has to be Mother 3, AKA the sequel to EarthBound. Though this project definitely had other issues, it eventually resurfaced on the GBA as essentially the same game in a different format--seriously, if you compare old, fuzzy screenshots of the 64DD and GBA versions, you'll find that that even the dialogue is identical.
We may never know if Resident Evil 0's 64DD version makes for roughly the same experience as the GameCube one--whatever portion of it they finished, anyway--but Capcom recently shared a video of this unreleased rarity to promote its upcoming HD version. Granted, it's barely a minute long, but it's the most we've seen of Resident Evil 0's 64DD version to date, so that's certainly something. Heck, we can at least see Rebecca Chambers eventually lost the goofy beret--I guess she figured out that she's starring in a Resident Evil game, not an episode of Blossom.
What I'm really wondering, though, is just how Capcom grabbed this footage. Based on the quality of the video itself looks, I'm guessing it's not a promotional piece thrown together for some circa 2000 trade show, which means some sort of emulator or debug system was used to capture this unreleased slice of Resident Evil 0 64DD. Showing off more of the game would just be a profit-free act of goodwill, but I'm hoping this isn't the last snippet of footage we'll ever see from this version of Resident Evil 0. If anything, it's inordinately fascinating to dip into an alternate reality where the N64 had a Resident Evil prequel to call its own.