There’s some pretty solid work here, including giving us brief shots of the classic Ma Kent and Alfred beginning to speak in such a way as to make it look like they’re actually beginning to speak the modern lines.
It combines actual audio from both Batman v Superman: Dawn of Justice with some from the original films as well.
The trailer, put together by Strider HD, is actually quite well done.
The vast majority of the visuals come from the classic film versions as well, though there are a few shots from Dawn of Justice as needed to fill out the setup.