View: https://www.youtube.com/watch?v=soAct9da20A
Subbed trailer. It seems like they added an amnesia subplot.
Kouji's pilot suit, a mix of his TFO and Mazinger Z suits.
Also, the Japanese site has been updated with more complete bios. This time it's explained the Grendizer can only be piloted by special people who have the "Starker"(? Maybe I'm missing something, スターカー) GN talent, whatever that means, and Duke is one of those. However, there's also an entire group of "Starker Knights" working for the Vegans, and you can see a Grendizer-like silver robot in the trailer. So, in addition to the Mazinger Z, we'll see a bunch of new Grendizer-like robots through the series.
The amnesia thing actually has some precedent for the franchise. In Gousaku Ota's manga, Duke begins the series unaware of his identity, having undergone a memory wipe so he could live on Earth in peace. This was then reused in the Grendizer Giga manga.