Though none of the cast or crew for Harry Potter and the Half-Blood Prince could be on hand to introduce the trailer, given that they're all in London filming the next one, the new footage in the trailer was spectacle enough. The movie seems to be diverging from the book a whole lot, plot-wise. We already knew that there was an added scene featuring an attack on the Weasley's home, the Burrow, but the new trailer showed us the first footage. It looks like there are some kind of fireballs, or fiery versions of Dementors flying through the house-- it doesn't really resemble any kind of attack we've heard of before in the books. It's also totally unclear at what point in the movie this will happen. Usually the winter break scenes feature snow on the ground, but this one appears to be taking place during summer or fall.
Speaking of Dementors, we saw more of them wreaking havoc on the real world, and even a shot of Dumbledore standing on a tube platform. Foreshadowing of his encounter with Harry near the end of Deathly Hallows? Or an indication that the book will focus on the real-world impact of the wizarding war? I think we already knew there'd be more than just that interaction between the MInister of Magic and the Prime Minister, but now it looks like we'll be in for some honest-to-God action scenes on the streets of London.
Dumbledore also has a line of dialogue that definitely isn't part of the book-- "Voldemort has chosen Draco Malfoy for a mission." Remember that in the book, Harry spends the whole time convinced Draco is up to something, while everyone else thinks Harry is just blaming Malfoy again for something he's not doing. But if Dumbledore says straight-out that Malfoy is working for Voldemort this time, that could change a lot of the direction of the story. In the book we don't know for sure that Malfoy is working for Voldemort until he shows up on top of the castle to kill Dumbledore. The mvoie seems to be focusing a lot more on Malfoy, based on shots of him in the trailer, so it might get a lot more interesting to watch him, knowing he's the bad guy.
And finally, the new trailer had a lot of glimpses of stuff we already knew form the books, but looks amazing onscreen anyway-- the Inferi crawling out of the lake to attack Harry (they look a lot like Gollum), Harry shouting "FIght back you coward!" at Snape as he runs away from the castle, and little things, like Katie getting attacked by the cursed necklace or Malfoy's magical wardrobe that allows the Death Eaters to enter the castle at the end of the story. It all looks pretty excellent, as has everything for the movie that we've seen thus far.
Alan Horn asked at the beginning of the presentation if we'd all forgiven him yet for delaying this movie's release from last fall to this summer. The answer is no, probably, and new footage like this doesn't make the wait any easier. But at least we know we've got something to look forward to.
