"War. War never changes." Fallout is a post-apocalyptic game set after a nuclear war irradiates America, causing mutations and horrifically burned 'ghouls' who are humans who didn't escape into a Vault and yet somehow survived the nuclear war. In this era, barter is the new economy, though bottle caps can be used as a more regular form of currency. Fall Out 3 casts you as a person living in Vault 101 who has to flee a rather complicated situation where the Vault Overseer tries to arrest you due to your father leaving the vault. You then spend the rest of the game trying to track your father down.
This is a game of quests. Many quests. Each new location you find may well have a quest contained there, either implied in various notes or a full quest that pops up in your quest log. In fact, you won't find a society in the game that doesn't have quests (except for the ones filled with drug-crazed psychos that attack on sight). If the town has people who will talk to you, they'll ask you to do things. This generally is blended into the game a bit better than in Skyrim where some of their requests feel a bit out of the blue: "Okay, stranger, take this valuable gem over to the merchant for me" though not by much.
If you're using so many quests in a roleplaying game, it's a good idea to keep a map handy to document where you have to hand in all of those quests. Oh, and some kind of quest log wouldn't go astray either. To really get the wide open sense of this place, you shouldn't go with the usual themes of the players having a choice of places to go and then getting the same quest wherever they go and having them follow that quest until they complete it. Oh no, they should have the opportunity to get a list of quests, choose between them, and then fulfill them in any order they please.
On the note of quests, one of the ones I really liked involved finding scrap metal for Megaton. I just like the idea of being able to slowly help this society repair their home and while it doesn't have much of an effect in-game, if this were a role-playing game there'd be a lot of mileage you could get out of it with a new and improved Megaton slowly emerging out of a quest pile.
In fact, that reminds me of one of the major opportunities that does come up in all of the Fallout series. The opportunity to bring certain societies or towns to ruin or prosperity through your actions and your choices. You can do this in Fallout 3 in a really big way with Megaton near the start of the game. You can also do it to great effect in Fallout 2 as well. In post-apocalyptic societies where a single can of baked beans can be the difference between life and death, there should be that chance to feel like you really are making a difference on a more visceral level than your usual 'well, I killed the killers' level that most games resort to.
There's also a huge map that you can roam all over and certain parts of the map contain key locations, whether just an interesting site of toxic waste and broken cars, or a small outpost, or a shop, or a quest-giving NPC. This makes exploration a key element of the campaign.
Your best bet to integrate this aspect into the game is to create a map similar to that found in Pathfinder's Kingmaker with some sort of grid design laid over it. This map would contain all of the key locations and some of the plot ideas. The grid could let you know where the players are and let the players know where they're going. Give the players a blank page with a copy of the grid over it and they can choose where they explore and you can tell them what happens when they go there. Afterwards, you could even give them a tiny photocopy of the hex from your sheet to glue into place so they can have a little icon or image to help them remember what was there. This won't necessarily break immersion since the nature of the adventures will mean that there might be many sessions between choosing one or more hexes to journey through.
Then there's the damage system where you can either take damage to your overall health or to your various limbs (requiring a more specific healing system at times where you select a broken limb to repair). This is probably a little bit too much paperwork for most people to enjoy although in a game where people must really try to avoid damage, having them crawl around because both their legs are broken or burned is kind of a cool idea. I wouldn't use this in a Fallout-style game just because of the extra clunk, but in a full horror game you might want to assign hit points per body part and then make random rolls to see which one gets damaged.
Since many of the horrors of a post-apocalyptic wasteland also relies on the terrors of the moment of apocalypse, which happened a fair while ago, Fallout relies on apocalyptic logs to let us know the last minute experiences of those who died during the initial fall out or even what the world was like pre-apocalypse. This is important because, well, let's face it. If Fallout were to be our future, we'd likely only see the apocalyptic moments so those are the moments that have the best chance to resonate with us.
This is an easy aspect of the videogame to bring into a pen-and-paper game. Simply create props of the documents they find or verbally ad-lib them on the fly when they find audio recordings or other such details. To do this, though, you'll need a good grasp on what people used to be like in that location and what sorts of issues may have arisen. It may be unrealistic, but do keep such logs to the more interesting moments. Even the boring "Hello Bob, I could use a spanner" emails should still add a few rich details to the universe, such as pointing out that the mega-corporation they worked for put all the spanners into some sort of time-share arrangement. Otherwise, don't waste the players' time describing boring moments that don't add anything to the game.
A campaign based around Fallout 3, or including elements of it, would certainly appeal to Explorers as you spend a lot of time roaming a wide open environment, seeing new societies, and choosing whichever mission most interests them at the time. It also works for Tacticians and Action Heroes due to the high and frequent levels of violence that allow for an ideal mix of sniping, sneaking, and just running up and smacking things. There are some notes and the odd case to solve for the Investigators and plenty of NPCs to keep the Communicators happy. So in the end, a campaign based off this videogame should work out for all of the play styles though the first three will have the most fun here.
If you'd like to take a look at the trailer to learn more about the game, you can check it out here. If you'd like to read the sort of tropes that Fallout 3 used, you can find them here.
For the next Game Translation, you have a choice of these: Left for Dead, The Sims 3, Half Life 2, Prototype, Skyrim, Deus Ex, The Last Express, Mass Effect, Realms of the Haunting, Alan Wake, and pretty much any survival horror or horror game. If no one picks anything by next week, it'll be Alan Wake.
If you want to see the list of games I've done thus far, you can find the Game Translation series starter over here.