The trailer is actually the Tokyo Game Show trailer from last year, shown behind closed doors at TGS at Square’s Mega Closed Theatre. However, unlike the last trailer, there was a lot more real time footage shown of the trailer and the first time dialogue is heard for the game.
The amount of time between this trailer and the last is shorter as the time it took between the E3 06 trailer and the Square sigma 07 event (not counting the Jump Fiesta 07 trailer) was over a year and a half.
Versus XIII is a spin off of the Fabula Nova Crystalis series which ties in FFXIII and PSP spin off Final Fantasy Agito XIII with Versus XIII being developed by Kingdom Hearts creator, Tetsuya Nomura. The gameplay is expected to be more of an action RPG, ala Kingdom Hearts, then turn based like its big brother FFXIII.
The second this trailer goes live, expect it on GOONL!NE.