Metroid
Ah, gotta love a game that knew the power of twist endings before the medium had really “gone there.” While talking about the Samus reveal in Metroid is pointless, as everyone knows about it and has talked about it to death, this would have been an awful list had I not at least mentioned it.
For the one person who doesn’t know about this, it’s simple. You play through the game as a badass space marauder, and because of gender norms thrust upon us by mass media and pop culture, we spend the entirety of the game thinking this character we are playing as is a man. At no point are we given ANY indication of that, but we just assume, because “80’s and space warrior” meant it had to be a dude, right? So when we beat the game and found out Samus was female, it blew many collective minds.
I would also like to think it helped to abolish some of the earlier mentioned “gender norms” for my generation. Oh wait, nevermind. Nintendo has gone on to sex her up big time in recent years, so scratch that.
Still, it was an amazing (early example) of a plot twist nonetheless.