A teaser trailer for BioShock 2 was included with its predecessors' October 2008, PlayStation 3 release, but so far we've yet to see any film of its gameplay -- until now.The debut gameplay footage is just shy of two minutes long, but in that span it offers enough detail -- for instance, both the user interface and dark, moist atmosphere largely carry over from BioShock -- to leave all the series' rabid fans salivating for reasons other than a bizarre literal interpretation of the descriptor.The biggest plot device addition to BS2 is the Big Sister, this clip's impromptu star. It's instantly obvious that her creators lifted design ideas from her Big Daddy predecessor, but in action she's far more agile than the hulking brute of the first BioShock.Honestly, the Big Sister seen here almost reminds me of Metal Gear Solid 4's FROG soldiers. Not only does she sprint, jump and generally seem to best the Brothers in every motor skill, she also attempts to off you in more varied, clever ways -- for instance, the set piece in which she slashes away parts of the enrivonment in an effort to crush you under millions of tons of rushing seawater.Exclusive Debut Gameplay See Also:2K: BioShock 2 Rumors Are UntrueBioShock 2 Features 'Big Sisters', Preview SoonBioShock 2 Dumps 'Sea of Dreams' SubtitleBioShock's ADAM Syringe Brought to Life