As announced by Ubisoft over the summer, development of Victory will be led by Ubisoft Quebec. It's expected that it will be the only "main" Assassin's Creed game released in 2015, and is currently planned to come out in the fall.
Kotaku described the seven-minute-long "target gameplay footage" video its staffers viewed as "slick" and said it could pass as an E3 presentation. The mission in the video once again pitted the Assassins against the Templars, and featured a grappling hook that allowed the assassin to go vertical.
Several stills from the video are up at Kotaku and they certainly look good, very Victorian and all that, but there is something irksome about seeing the next Assassin's Creed—even by way of leaked footage—while the current game is still such a mess. At the time of writing, Ubisoft had not commented on the video.
Update: Moments after this article was published, Ubisoft replied to our request for a statement:
"It is always unfortunate when internal assets, not intended for public consumption, are leaked. And, while we certainly welcome anticipation for all of our upcoming titles, we're disappointed for our fans, and our development team, that this conceptual asset is now public. The team in our Quebec studio has been hard at work on the particular game in question for the past few years, and we're excited to officially unveil what the studio has been working on at a later date. In the meantime, our number one priority is enhancing the experience of Assassin's Creed Unity for players."