According to Andriasang.com, they showed gameplay footage:
http://www.andriasang.com/e/blog/2009/09/2a4/playable_ff_versus_xiii_footage/
http://www.andriasang.com/e/blog/2009/09/2a4/playable_ff_versus_xiii_footage/
While we've been seeing realtime footage of Stella and Noctis's first meeting since last year's DK-something-something-90210 event, the new TGS video offered a first look at gameplay -- that is, someone was clearly moving a character around. I'm pretty sure that character was Noctis. A series of clips showed Noctis moving around through the streets of a European-style city, first surrounded by other people, and then alone at night. Next, the footage switched to Noctis moving about a vast field. Here, he was joined by monsters, some massive. I was actually reminded of a scene of Hope running around FFXIII's vast Pulse fields in the TGS FFXIII trailer.
When referring to the Versus XIII TGS showing, I use "footage" instead of "trailer" because what we were shown wasn't actually a trailer. The footage was all off-screen, filmed off presumably development units by the development staff. It was set to the same music from past trailers, but there wasn't any attempt to make a promotional trailer out of the various gameplay clips.
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