Hard to say, seriously. I mean, you need to communicate with Steam to even startup the current games connected to Steam... How will HL2 be any different? You'll NEED to communicate with the Steam servers to validate the game. If the servers are clogged to hell, then this won't be happening...
Well, no one knows how big the game is... Or how much will be streamed days in advance to people through Steam. It's quite possible that the majority of the game will be downloaded days before the game is offically on store shelves, and the only remaining data left to download on the 30th is...
Actually, I believe there are quotes from Gabe saying the game should be on store shelves on the 30th... But, of course, everything is subject to change. Perhaps they need those extra few days to polish up the game. Who knows.
He's saying that the game will be shipped to retail stores a few days before the release date. The stores should start receiving the game on the offical release date (which is September 30th), which is the same day HL2 will be available on Steam. Gabe is saying, though, that it's possible...
This is what I've found most interesting when thinking about all of this. We've heard a definate "No" to TF2 being the multiplayer for HL2... But a "No comment" regarding CS2 for HL2's multiplayer. It just makes me suspicious.
I certainly did notice, I just wanted to voice my opinion. CS2 must be like the original CS is Valve wants to continue making money on the CS franchise.
Not to sound rude, but CS isn't Ravenshield. It's not meant to be totally realistic, it's more of an action/strategy (with emphasis on action) hybrid then anything else. By taking away the core action elements and trying to make it more of a slow, strategy based game, Valve will be alienating...
Well, considering Valve has said that any game genre can be made with the Source engine, I'd assume making a 3rd person perspective would be quite easy for someone who has the skills to make a mod.