Time for a runthrough of what I saw in that conference then? I haven't seen others talking about this stuff so much, so I may as well dump it all here:
Power Armour:The modular system also means that each area independently takes damage (as shown by them turning red over time).
It can over heat.
You step into the armour rather than carrying it around in your inventory as before. Its worn over the existing character model. That you don't carry it also implies that you can step out of it if its wrecked and just leave it somewhere.
You can customise your armour with additional paint schemes (military, Vault-Tec, Raider). Also add on things like "Lead Plating" and "Explosive Shielding".
Raiders of various classes are seen wearing power armour. It has a raider feel to it however, so presumably the player can take the Raider bits and mix them in with their regular suits or maybe remove the raider bits entirely.
Creatures:Ghouls are seen without limbs, which may tie in with the ability to strip away parts of an enemy as you fight (the Synths lose parts of their faces).
Mirelurk Queen/ Molerat Queens. There is one piece of concept art for a King too.
Aliens feature heavily in the concept art, as does a an astronaut's suit (which is seen in game too).
There are
a lot of images of cute kittens...
Super Mutant seen wearing a Chinese Ushanka. More on the Chinese later. =P
Super Mutants are seen to have a mutated dog thing with them. A dead one's seen in game. I see Centaur concept art though too, so the guard dog role may be split between the two.
Mutant bats are a thing. Mutated birds, ravens, seagulls too. As well as mutant deer.
A robot that looks a bit like the Nutcracker carrying an energy gun in the style of a sword.
Other than the regular ghouls, that are a lot more human looking now, there appears to be another type that look more craven, like the Falmer from Skyrim. They're seen in a tunnel in game.
World:Looks to be a single cell rather than multiple smaller ones that are linked together. This is corroberated by your ability to fly a vertibird and use a jet pack (which would be a bother if there were invisible walls everywhere). Also building's can have interiors in the open world too, but I doubt that larger buildings exist in the same cell for performance reasons (could be wrong).
There's going to be a coastline, with wrecked ships and a lighthouse. The docks will be an area, and it appears there'll be a friendly settlement there (also a Raider one hosted in a drydock). Notably however there's a Chinese sub beached too. What implications that has in relation to the "Masterbrain" aren't clear, but given that the Shi's submarine had a super computer in it may mean that the Institute wants you to go there at some point.
Similarly a marsh is seen too, with ghoul like inhabitants. A dead forest appears as well.
MIT looks really old and disused. For a place that's supposed to be a mecha of technology this seems odd, as in perhaps the people are all in pods or dead and there's nobody there to maintain it. There's a picture of a rather stately room with men in suits standing about in the concept art too, might be in MIT.
An airport's in the concept art too. I say airport, those planes look a lot like the Imperial transport thing (the one with the three wings) from Star Wars. Could be a space port given the aliens...
The Memory Den is a bit like a Chinese Opium den, apart from with Tranquility Loungers. Good opportunity to go and play some cool simulations.
The Building System. You can only built in set locations. Presumably to stop you from say building a wall in the middle of a corridor. This makes it easier for the AI to work, though I would have liked doing up a random city apartment. Mods will sort this out however.
Could be a ten pin bowling place too, given that there's concept art for bowling balls and a bowling outfit.
A factory of some sort. With a crucible full of metal.
An disused Vault, possibly the player's appears. However I don't think its the players as their one has skeletons in it (and we're told everyone's dead), whereas this has people. I think that I saw a raider Vault too.
Mass Effect looking pre-fabricated huts are in the art.
People:Possibly linked to MIT, there's an image of people with a hell of a lot of cables coming out of there head.
Baseball style armour features heavily in both raider and civilian dress.
Ghoul captain of the USS Constitution. Related there's concept art of people in Colonial British red uniforms, similar to the Ghoul's outfit.
Brotherhood Scribe's outfits haven't changed much. Like a lot of the returning stuff its just a revamp of the existing design.
Pretty large range of hairstyles. 27 at least.
Weapons:The Minigun overheats.
A conventional (man portable) tactical nuke appears in the concept art too.
Story:Its the player character, Megaton style, that sets off that nuclear strike in Boston. There's a controller to the left of that image.
Presumably you'll be able to side with the Brotherhood or their opposition. You're seen fighting alongside them in game and in the concept art, but also fighting them too. The Prydwen Airship has Brotherhood insignia, whether or not you're the one who shoots it down or someone else does it up in the air.
Raiders have taken over a museum. Seems to be related to that leaked Kotaku script that had the player siding with some militia to fight the Raiders in that location. Militia feature in the background of concept art of the player fighting alongside the Brotherhood. Lots of images of American War of Independence paintings and posters too.
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I'll leave it at that, as yes I could make commentary on the known features, but I think people would be more interested in the stuff people aren't talking about. Anyhow, plenty to mull over in terms of what we've already been building over the years and how the designs have changed. I'd say that anyone who's already making mutants based on Fallout 3 is still fine to do so, as let's just say that the difference in mutations is by region. Similarly with armour the same goes, as in they're different variants.
Here's a site that has all the concept art images on it that were shown as a blink or you'll miss it sequence.
http://fallout.gamepedia.com/Blog:News/The_Fallout_4_E3_Showcase