OK, this is going to sound a bit… sociopathic. Or perhaps psychopathic. In any event, it's something that I'd only do playing a game — I swear! 🙂
I will soon finish Point Lookout for the second time. It's the last bit of DLC for Fallout 3 in this, my fourth run-through of the game. I will have accomplished most of my goals (having gotten all but 20 of the unique weapons and articles of clothing). After I finish Point Lookout, I'm going to be a bit on the "bored" side in terms of X-Box gaming until New Vegas comes out.
So until then, I was considering going on a personal challenge to obliterate all of man- (and ghoul-) kind in the Capital Wasteland. I know that random encounters will still pop up, but I was figuring on going to every town, every settlement, every everywhere, and wholesale slaughtering everyone I came across.
Aside from the obvious ramifications — shops no longer being available, so no trading to be done — what are the ramifications of making a "last man in the world" (well, at least the east coast of the US) situation in Fallout 3?
Update:
If you're gonna do it, have fun with it! Pint-Sized Slasher Mask and children's Blast-Off Pyjamas FTW.
Best Answer
Unfortunately, I'm not sure your goal is achievable, as there are generic citizens in some of the major cities -- "Megaton Settlers" and "Rivet City Guards" for instance, that while you may wipe out all of them for once, they will eventually respawn.
The other issue is that you are unable to kill children (with good reason!) so the children within Megaton, Rivet City, Little Lamplight, and assorted other locations will still be around.
As to actual ramifications, the biggest would be repair. Some of the best armor / weapons in the game (or at least, the most unique) are either hard to come by replacement parts, or flat out impossible (in the case of T51-b Power Armor, Chinese Stealth Armor, etc). You'd want to make sure you either only use equipment that you can repair on your own, or face the grim reality of your coolest toys breaking.
Though after you've killed every killable NPC, what exactly do you have left to kill anyway, hm? :P