The public has only seen the original trailer and extended one. The press (or whoever got into one of their closed mega theaters) has seen 4 or 5. Here's something i know about FF13.
-Main character is female (duh)
-Summons has more functions than in battle.
-There's a world map. (hurray!)
-There's a large floating city/ or space colony called "Cacoon"
-Crystals protect "Cacoon" and keep the city going
-Everything outside of "Cacoon" is called "pulse"
-Crystals also have the ability to create objects and living things.
The only thing we have been kept in the dark on is the battle system.
But if you guys REALLY want to know why SquareEnix is so quiet on FF13 info... It's because they want to annouce the 360 version (via same day launch) before they start building mass hype, duh! **runs away**
