I’ve seen a couple of these now and I have to say I love them. These are classic NES games that have altered sprites to allow the protagonist to be the female. The two games in question are Donkey kong and Zelda. Both featured a damsel in distress with our protagonist being a male.
A quick patch of the rom file replaces the sprites for the protagonist so that you can play as the female version. Pictured above is Zelda Starring Zelda by Kenna W. You can find some information about how it was pulled off on her blog.
The first one to make waves for this was Mike Mika’s alteration of Donkey kong. You can see a video of that below.
If we’re going to talk about strong female leads in old video games though, we can’t forget the masterpiece that was Metroid.