While Edwards himself had not played the original Fallout games before, one of the others mentions that the game is more in tune with them than Fallout 3 was. It is also mentioned that much of the game is based on Van Buren, the game having the same framework and factions.
“They seem to play at a lot of that when they do the presentation. They understood what made Fallout 1 such a success. I spoke to Josh [Sawyer] and Chris [Avellone] of Obsidian and they were very heavily involved in Fallout 1 and 2 and both of them brought up that Fallout 2 was actually a little bit off of what they wanted Fallout to be. It was too funny, too silly, too stupid, there's too many pop culture references in it. I'm very well aware it can sound a bit cynical when you say "They were very complementary about Bethesda" because they're giving them an enormous amount of money to make a Fallout game (...) The one thing Chris Avellone said about Fallout 3 is if they had the technology Bethesda did to make a Fallout game, it would have been very very similar to Fallout 3. One thing - in his words - Fallout 3 "friggin' nailed" was exploration.”
This is actually not correct, since at Black IsleChris Avellone only worked on Fallout 2 and J.E. Sawyer only worked on Van Buren - none of them worked on the original Fallout.
Among other things, they mention that Karma was broken in Fallout 3 (e.g. you lose Karma for stealing things from a family of cannibals in Andale) and the New VegasReputation looks much better and should replace Karma altogether, discuss the weapon modifications and hardcore mode, and talk about how terrible Games for Windows Live is and how it is a shame that New Vegas uses it.
Another quote by Edwards:
“There are some gambling minigames, I think. Don't quote me on that. (...) What was interesting is that they literally didn't show anything coming from the skyline of Vegas during the demonstration. It's probably the place in the game that hasn't really had any attention or isn't up to the standard that they're willing to show it. Specifically asked I want to do ghoul crooner. And I think Josh said "Everyone always asks for ghoul crooner" in the game, so it's almost certain to happen. (...) I don't think the Vegas in the game isn't going to be near as big as people are expecting. Expect it to be at a similar scale to Washington, rather than a GTA-style city that you're exploring in a Fallout world. (...) It's Vegas of the 50s, so it's a Fallout Vegas, not a Vegas of today. There are specific landmarks in it that are similar to what is available today, one of the highlights of the Vegas skyline is the Stratosphere. (...) There's a building that's very similar to the Stratosphere in [New] Vegas that you can see, but it's more like...it's very tall, but in shape it's actually like the Landmark (...) Their art style is specifically the 50s vision of what the future would look like, is what their art director said, I think. You're looking at making a Vegas of what people in the 50s thought Vegas would look like, rather than Vegas today.”