For starters, fans of the original games need to know this: much of what you loved about Fallout is in there. The Pip-Boy has been faithfully updated, as has much of the character stat system, and the turn-based aiming mechanic. While the combat in Fallout 3 is not turn-based, you can enter the VATS system to target individual body parts of your opponent, and allocate action points, then watch as your character cinematically executes the attacks, often triggering explosions of gore.
The look (the vault is surprisingly familiar), feel (guns, ammunition and violence all have the same "grit" as before) and humor (Mr. Handy calls you a stupid git behind your back) of the Fallout world has survived, been updated and made new. Although the new game is in 3D, and features a first-person perspective, it's still Fallout. It's the same world. It is new, but the same. I can't say this enough. Change, in this case is good.
Still, to the chagrin of some, it is, in fact, much like Oblivion meets Fallout. It is first person, NPCs do feel more like Bethesda NPCs than Black Isle NPCs (although the dialogue options are still hilarious and wonderful) and the world feels much more malleable. In Fallout, one always felt as if the world was what it was, and you would live or die without making much of a difference. War, after all, never changes. You could stomp out the bad guys if you wanted, but that would leave only a gaping hole, not rejuvenate the world.
I get the feeling from this demo that Bethesda's Fallout will feature much more quest feedback, and perhaps offer the chance to change, if not war, then perhaps a few lives. And although this lessens the sense of alienation and isolation, that isolation may not have been entirely planned to begin with. After all, a lot of PC games from that era felt "isolated" merely because they were. The technology didn't yet exist to create living, breathing worlds. Bethesda's improved radiant A.I. and unparalleled world-building expertise have combined to create a much more immersive experience, and while not exactly the Fallout you remember, is still Fallout.
While it's impossible to say whether or not the finished game will please all fans of the series (or even newcomers) based on a staged 45 minute demonstration, I went into the presentation expecting to be at least a little disappointed, but I was not. The degree to which the Bethesda team remained faithful to the word of Fallout is staggering, as is the level of detail and ... there's no other word for it ... "love" put into the game.
This is another one I'll definitely be picking up (in Fall 2008), and it will go right up on the shelf beside my original copies of the first two games. Right to the left of the space where Van Buren would have gone.