Over at Nerdist, my former editor Brian Walton has a description of the footage, with some potential SPOILERS. A sample:
The tram dangles precariously as Aaron Taylor-Johnson reaches out to save his young ward. But even if he does, who will stop the creature destroying the airport? Who the hell do you think? In the most heroic reveal for a character that has already caused mass destruction, the King of All Monsters steps up to put a smack down. With a a massive roar, we get our first full look at the original big bad ass. And he is gorgeous! A perfectly updated look of Toho's creation stands before us. Massive trunk legs and all.
But there's more. Thanks to intel from our man on the ground, Fred Topel, we can give you a slightly better picture of what the other creature is...
I showed Fred this toy image that joeyg814 shared with us in comments the other day. According to him, it looks just like this, minus the red bits.
I've also been hearing that the while the kaiju are original creations, you might see a few easter eggs that may remind us of more familiar critters.