This is a new one -- in order to promote its new iOS title, Rainbow Six: Shadow Vanguard (coming to the App Store tomorrow), Gameloft has put together this interactive trailer over on YouTube. Not only does the trailer show off some gameplay of the upcoming title, but it also allows you to actually make decisions as you watch about how exactly to play the game.
I can't say it's entirely successful (though the game looks pretty good -- Gameloft is doing well at aping most gameplay styles for the iPhone, and in this case, they're doing it officially), but it's a really interesting way to market a title, and when it comes to the App Store, that's often one of the biggest priorities. You can see the trailer in action after the break.
Apple iPhone 6s