It's not really a trailer, just the Grid VFX Concept Test stuff from last years Comic-Con cleaned up and finally released to the general public.
It's not the same teaser. They reshot it. Flynn is different (in the original, he's bald; here, he's got hair). Also, in the original, Flynn lives in a glass walled enclosure above the game arena. Here, it's a mountaintop retreat thing.
The game arena itself is a lot more elaborate in the second version, as well (the original doesn't have the canyons or most of the other stuff like the spiral staircase thingy). And the 'blue soldier' has more dialogue (in addition to "it's just a game", he also says "You won, okay?"). Plus, the blue guy never showed his face in the original.