Final Fantasy 15 rolled out a new trailer this weekend for Jump Festa 2015, the enormous convention over in Japan. It features some bursts of gameplay but the majority of it comprises cinematics establishing the game's story.
Notably, the character of Cid now is a woman named Cidney. The rest of the trailer teases out details that director Hajime Tabata addressed or answered in a Q&A with fans at a Jump Festa panel. Kotaku had a reporter at the event and published a very detailed transcript of Tabata's remarks, so be sure to check that out if you have a specific question in mind.
One question that isn't answered is when this game is coming out. For now, it's just "now in development." For more Final Fantasy 15 video, see these seven minutes of gameplay, with Tabata's commentary, from Tokyo Game Show 2014.