Long before EA released its 2015 Star Wars Battlefront reboot, Free Radical Design whipped up some—possibly most—of the third game in the original series, Star Wars: Battlefront 3. Sadly, and for reasons that I don't think have ever been fully clarified, it never saw the light of day. But every now and then we catch a glimpse of what might have been, most recently in a chunk of gameplay footage that's turned up on YouTube.
The video apparently covers the first part of the game's first mission, and showcases a squad of clone troopers fighting off a horde of battle droids. The audio is terrible (take care if you're listening through headphones), but the mission itself looks pretty near to complete, it not exactly flawless.
Given how close to completion it appears to be, FuZaH, the YouTuber who posted the video, expresses hope that EA will finish the game and release it as Battlefront: Legacy. It's a nice thought, but I wouldn't hold my breath: Even if EA was minded to release a game that might distract a portion of the current Star Wars Battlefront audience, I rather strongly suspect that its licensing deal with Disney would preclude that sort of freewheeling.
Previously released clips of Battlefront 3 gameplay can be seen on FuZaH's YouTube channel.