Sometimes it's exceedingly difficult to describe a game in just words. This is especially true about games that are visually unique and introduce gameplay elements no one has ever really seen before. "BioShock Infinite" is definitely one of those sorts of games. The demonstration you're about to see was what led me to pick it as my Best of E3 2011, and hopefully you can understand why summarizing the contents of the demo into 750 words or so is a mentally trying experience. Really, words just don't do it justice.
The E3 demo first aired on Spike's GameTrailers TV, and they've posted the entire episode online. If you're looking to jump right to the demo, it starts at around 4:30 in the video below. You may have to sit through a couple of commercials to get there, but trust me, it's worth it.
Are you beginning to understand why I can't wait to see more about this game?
If your curiousity is piqued, you might want to check out my two-part interview with Ken Levine, in which we discuss some of the finer points of the demo, including Tears, Nostrums and Vigors. Or you could just watch the video again. There's a bunch in there that you're likely to have missed. For example, did you notice the song playing after the horse sequence?
You might also want to go back and give the original premiere demo a watch. It's fascinating to see just how much has changed in the six months since we saw the game last.