In Bethesda’s world you can slap together whatever mish-mash of stats, items, and perks together and still be able to shoot, talk, and VATS-cheese your way just fine. Black Isle comes from a pen-and-paper tradition that emphasizes reality. You can’t rest for an hour and get a full health regeneration. There are no autosaves. The bad guys that can one-shot you are prowling around the second you step out of the vault. There are ramifications. If you do something silly, like say, roll a character with extremely low intelligence, you’ll find that
all of your dialogue choices are replaced with brutish grunts. Your first quest has a 150-day time limit on it. You can kill children, if you’re sadistic enough. There’s a real primalness here.
Fallout 3,on the other hand, is designed for the broadest palette possible.