The glitchy transmission starts off with Shannon gravely intoning: "YOU ARE NOT ALONE." It's actually pretty spooky and effective, as Shannon goes on: "My name is General Zod. For some time your world has sheltered one of my citizens. I request that you return this individual to my custody. To Kal-El I say this: surrender in 24 hours or watch this world suffer the consequences."
To those who don't make the weekly pilgrimage to the comic book shop, Kal-El is Superman's Kryptonian name and General Zod was a military leader on Krypton who was banished to the Phantom Zone after an attempted coup (in "Superman" and "Superman II" he's portrayed by Terence Stamp and the character showed up in the TV series "Smallville," this time played by Callum Blue).
While some new footage would be nice, a second trailer seems to be imminent, and the scary, Al Qaeda feel of the transmission lends it a nice real-world intensity (perhaps thanks to producer Christopher Nolan, who directed the allegorical Batman trilogy). Plot-wise, too, it gives us a vague understanding of what the movie is about and why Zod is attacking earth. This bit might be brief and fuzzy, but it's still exciting.
"Man of Steel" opens on June 14th everywhere.