I think they meant Midgar is disk one. The trailer showed inside ShinRa headquarters, which would be an end game thing if that was the full game. If that's all they really had to show until March, then that would be insane. Also Midgar 5 hours to complete. Unless this is a 20 hour game there isnt anyway they can really fill that much story in. The game is likely until Junon or Rocket Town.