And it's a trailer we've already seen
During Sony's announcement event for the PS4, Square Enix announced that their Luminous Engine would be powering games on the PS4. They followed this by playing the same gameplay demo shown at E3 last year (seen above).
So, apparently, they wanted to reassure us (and possibly investors) that their hot new stuff is going to work on the hot new hardware? What a tremendous use of a rapt worldwide audience.
Check out ALL the PlayStation 4 coverage from today's event here. Console specs revealed, new controller detailed, and tons of games announced!