Fallout 3 broke just about every plot line about Fallout 1 and 2, completely reverted Super Mutants to barbarians despite the fact that they've tried to reform during Fallout 2, completely ignored the entire political cause of the Super Mutants, gave the Brotherhood of Steel armor that didn't even exist before, redesigned most of the weapons so they didn't match the ones before, completely destroyed almost all continuity between 2 and 3, made the Enclave a Super Badguy McBaddie whereas the Fallout 2 one was actually pretty subtle with it's actions, and completely ignored that people fucking need food to live (where does the food to feed Megaton come from?)