Unfortunatly, the game is delayed. We've had a few confirmations, and since the game just isn't done, it won't be coming out on the 30th.
http://www.halflife2.net/forums/attachment.php?s=&postid=193426
It's not Nvidia's fault, it's not ATi's fault, it's not the government's fault, it's not anyone's fault except Valve. They still need time to make the game the way they want it. This is the truth.
I don't see a problem with this. When you send an e-mail to Valve, it doesn't mean they have to be all professional. They're real people, responding to their fans. There's no rules requiring them to spell correctly or use proper grammar. Hell, half the people here can't spell or use gammar...
It's offical that the game ISN'T done and that they will be revealing a new release date as soon as they figure out how long it'll take to finish the playtesting.
The tech demo? Yeah, probably. There's not a whole lot in the tech demo, just a lot of cool effects.
As for Valve's silence... Yeah, I think they should stay silent about the story at least. I don't want the game's storyline ruined AT ALL. I have no clue what to expect with the story, and...
If the tree was modelled and coded to be cut in half, then this would be possible... Trees and stuff won't just automtically be like that, though. Remember that Valve specifically made the zombies so that they could be cut in half. They wouldn't be that way otherwise.