People overlook Contra. if you didn't put in the cheat code and you played straight up with only 3 lives to try to beat the whole game, chances are, you were not beating it even if your mom's life depended on it. Also Mega Man 1 on NES? [i]Brutally[/i] unforgiving game. I'd also have to say that the invincibles in borderlands 2 are some of the hardest bosses that gaming offers on Op lvl 8. They're not called invincible for just any reason.