Gamer's Guide to Life has posted an interview with answers to the questions they asked users to submit to them back in May. Unfortunately, the delay meant that there isn't really much new there. Here are some of them:
Can you modify and look down the sights of every single firearm? Are there any new types of weapon - we've seen flame, plasma and ray guns in Fallout 3, but will you add any new ones?
Yes, every firearm has 'true' ironsights (this is actually a mode that can be disabled, for players that prefer the 3rd-person shoulder cam). And as far as I can recall, every firearm has at least a couple of mods. Overall, we’ve got about double the guns that were in Fallout 3. Players will also be able to use different ammo types with weapons.
How many perks from Fallout 3 will reappear, and how many of your own are you adding? Could you possibly spill any examples?
The majority of Fallout 3's perks are back (some are modified, some were removed), and we've added quite a few of our own. We should have more information on that soon.
Will there be a weather cycle?
No. We did, however, completely redo the sky and times of day, so look forward to some scenic sunsets!
Will it be possible to max out all skills in one playthrough? Will there be many different endings (not just variations on a few opposite ones as in Fallout 3)?
If it's possible to max out all your skills in one go, no one's done it yet! There is more variation to our endings, as they depend on your reputation with various factions, actions you've taken, and companions you've recruited.”