* First and foremost, the game will take place in Boston, and be kind of a direct sequel to Fallout 3 with a few groups returning.
* From what it sounds like, "The Institute" is pretty much the downtown DC or New Vegas of this game. Boston is going to be unlike anything we've seen in a Fallout game before, with buildings more on par with cyberpunk and retro-futurism.
* Androids play a big part in this game. The railroad from Fallout 3 is a faction. The enemies of the railroad is "the Plantation" -- a group who force Androids to farm so that Humans can get food. The Institute is highly advanced and probably obtained or built their own GECK to start a farm.
* Due to complaints about using Super Mutants and the Brotherhood of Steel in Fallout 3 excessively and going against the lore too much, Bethesda has decided to avoid using these groups. Bethesda wants to make a new "race" (think Ghoul, Super Mutant) which will be central to Boston. Bethesda is currently looking at Lovecraftian fiction since Boston is around "Lovecraft Country".
* Bethesda has no plans to reinvent the leveling up system to make it more like Skyrim and want to make Fallout 4 more distinct from Skyrim since of the complaints that Oblivion and Fallout 3 were too similar. Bethesda is thinking about introducing a system, similar to Skyrim, where your skills can level up if you perform certain tasks