The introduction's voice-over mentions "confirmed reports of nuclear detonation," and notes: "War. War never changes." Following that somber opening set to "It's All Over But the Crying" by The Ink Spots — a group whose music has been featured frequently in Fallout games — the trailer leads the Vault Dweller out of Vault 111 and into the wasteland. From then on, we see shots of post-apocalyptic society, including a few recognizable Boston landmarks:
Bunker Hill Monument
Massachusetts State House
Paul Revere statue / Old North Church
Later in the trailer, we see a nuclear bomb go off, with humans left stranded outside a Vault entrance. It's possible that the woman holding the baby in that segment is the same mother seen earlier in the trailer, looking at her baby in a crib along with her husband. Their house is still standing, but that's about all that can be said for it.
Here are some other Fallout universe callbacks from the trailer:
Mister Handy robot
Protectron robot variant
a Mirelurk, perhaps
There are also plenty of details to be found in the "Welcome Home" artwork that Bethesda posted on the Fallout 4 website. It looks like the Vault Dweller's home base, and it appears to be the garage of a Red Rocket gas station.
Aside from the obvious items, like a Nuka Cola machine and a set of Power Armor from the Brotherhood of Steel, we see that the garage is being used as a storeroom for an arsenal of weapons (along with the rifle leaning against a chair outside). The peg board on the wall holds a laser rifle and other firearms, while a minigun sits on the floor under a cover. There's a rack holding comic books, like the collectibles in Fallout 3 that conferred skill boosts. And of course, it seems like this furry friend will be the Dogmeat of Fallout 4.
Bethesda launched a teaser site for the announcement 24 hours ago, asking fans to "please stand by" for news. The site briefly went live this morning, earlier than expected, revealing some images and details about the game. Fallout 4 is in development at Bethesda Game Studios on PlayStation 4, Windows PC and Xbox One. Bethesda Softworks will provide more details at its pre-E3 2015 press briefing, which begins at 10 p.m. ET Sunday, June 14. You can watch the debut trailer below.