Sitting in Bethesda's temporary European HQ in the heart of London's trendy Soho, just near the excellent Red Lion pub and some brothels, Bethesda's resident do-everything man Pete Hines is extolling the virtues of the free-roamer RPG.
"I could tell you what you'd be doing every single minute of Call of Duty 4,"
he begins. "Don't get me wrong - that game is fucking amazing, but I could tell you what happens in every minute of every single mission within very small parameters. What weapon you were using... everything.
"With Fallout 3, you could be 10 hours in and I couldn't even guess 20-30 per cent of what you'll have done. We made our reputation by doing big and crazy - things people hadn't tried before. We feel that we've gotten good at it now."
This much is incontrovertible, the open-world structure of Oblivion was sometimes seamless to play through and the AI-driven daily routines of Cyrodiil's denizens a delight to play around with. The same will be true of Fallout 3, when you're out in the wastes.
"You could be walking along and there'll be a diner off to the side, you'll wonder what's over there - and it'll turn out to be a Raider base and there's mutated bodies hanging from the ceiling," explains Hines.
"Suddenly the Raiders could show up - and that's just due to the time of day. If you want to play the game hardcore, you can sit and wait and watch these guys over a period of time and figure out what their schedule is - go in while they're out, or when they're sleeping."
The start of the game though, as it was with Oblivion, will be inherently linear - although perhaps not in the temporal sense. There's probably no need to bore you with the way the action cuts in and out of various events of your childhood, nor with the fact that many of your perks, stats and abilities will be selected at various points within this.
So let's just cut to the meat and reveal that when you're born, a left-click of your mouse will make you cry. And then, when you're a year old and escaping from your wire-fence playpen, the same button will make your character say stuff like, "Dadda!"
No word if you can go rooting though Liam Neeson's cupboards and valiantly attempt to drink bleach just yet though.
As soon as you're out in the wilderness in your late teens, everything opens up before you - the landmass is smaller than that in Oblivion, but Bethesda insist that it won't necessarily feel that way.
"When you started Oblivion you had all these cities around that you knew about - you could travel all over the world, then explore from each one," says Hines. "In Fallout 3, you emerge from the Vault and you don't know shit. You're not getting anywhere in a hurry."
The idea is that being forced to travel around on foot, with no real idea of what direction stuff lies in, will force you to appreciate your immediate environs more - as well as give you a strong sense of exploration.
Much as in the original Fallout games, where you'd only be told settlements were vaguely to the south or were completely unmarked.
This 'less is more' ethic extends to NPCs as well, having a more limited number of wordier tykes milling around, rather than the hundreds of three-line conversation 'tell me rumours!' variety that inhabited Oblivion.
In the new scenes on show in Pete Hines' presentation, the improvement was marked - when bickering with a childhood bully there are at least six or seven different retorts to your foe, for example.