Ok, so we know that the protagonist is a war veteran. We also know that after you emerge from the vault you are able to almost immediately (it shows level 2 on the Xbox demo) get into some power armor. This leads me to assume that while in the military you have previously had power armor training. If that is the case, perhaps you are needed to help with the citizens in panic at the vault entrance and are asked to get into some power armor. This probably would allow you to survive the initial blast and give you a chance to descend into the vault. Its from there that we continue with the cryo sleep assumption until you awaken 200 years later. Of course the other viable option in my head is that you are already inside of a cryo sleep tube about to be lowered into the vault as the bombs go off. Or, one final guess would be that the initial blast is too far away to do harm initially... instead only looks bad due to the shock wave.

One additional thought about the cryo sleep scenario. What if the cryo beds are set to open once every year. This would perhaps explain why he wonders if others are still alive... but I don't expect family to be one of those. Perhaps other NPC's though that helped with the initial cryo sleep. (although I am also completely aware that Todd says 'you emerge as the sole survivor of vault 111)

Thoughts?

Except we clearly see in more then one video youre clearly standing next to your spouce and child, still a civilian when the nuke hits, your survival due to already standing by the elevator to vault 111 by the time it happened.

Perhaps the shockwave is not strong from that distance, you see the trailer shows the sugar bomb stand still on the table

since the bombs hadent fallen yet by then, it be kinda hard for the suger bomb to fall over

he means during the dog sequence when he is exploring the protags house i guess. But irelevant at this time, seeing as someone already said what invalidates the got in PA theory

You, as in the Protag, stand in civilian clothing next to your spouse and child, right when the bomb falls. Wether the bomb is close enought to harm you or not is a different discussion, but you're definitly not standing there in Power Armor.

Remember... Codsworth is still there. He would put the Sugarbombs back on the table, because he is a clean robot

Realistically speaking,if you ever looked at an atomic explosion with unprotected peepers you would be blind.also the sole survivor would be dead but the game might elaborate on why he is still alive.
So far as Video game logic goes, it looks like the sole survivor was thrown in the vault by the explosion.

Which be might impressive since he is standing at the raised vertical elevator you need to use to access the horizontal vault door.

We have already discussed this a lot, but to restate we can come up with lots of reasons why the Protagonist shouldn't survive a nuke to the face and reasons why its possible but in the end it comes down to PLOT ARMOUR!

The protagonist survives becuase he/she has to, much in the same way how the Courier survived being shot repeatedly in the head in FNV or the Lone Wanderer survives being transported across DC by his/her father as a baby and then gets into a vault that is then sealed through his/her childhood.

Logically and realistically the F4 Protagonist is royally screwed, but due to the magic of plot armour they survive to continue their story.

Maybe cause he was in the militarty they have gave them some drugs like Rad-X or such.

Simple. He and Nora both injected themselves with a mysterious Plot Device serum. The same serum Augustus injected himself back in Fallout 3. We open the game mere minutes after they put away the mystical serum and syringes.

Same reason you don't die using a fatman.

You mean... my breakfast is still there? You have no idea how happy this makes me! 200 years is a long time to be cryo-asleep. I'm going to need the calories.

The player character survives the blast because Fallout nukes aren't very strong, explosive wise.

It was stated as far back as Fallout 1's game manual that nuclear weapons in the Fallout world had stopped being like then nukes we have today, and instead had exchanged pure explosive power in favor of far greater radiation output.

If that's true then it explains how they would survive long enough to be lowered into the vault, they were literally standing on the lift!

As for what happens in the vault, I'm guessing enclave/brotherhood.

It also explains how most major cities still have vast, and fairly intact, ruins, despite being hit by numerous nuclear weapons.