The Guardian Legend

The Guardian Legend is an action-adventure game for the NES where the player controls a transforming gynoid named Mia (the Guardian) to save Earth by destroying a giant, alien-inhabited planet-like object called Naju before it collides with Earth. The game seamlessly blends two gameplay styles: top-down exploration in an action RPG-style overworld and vertically scrolling shoot-'em-up segments in linear corridors, known as "dungeons". Players must explore the labyrinthine world to find the ten safety devices that will activate Naju's self-destruct sequence, while also upgrading their weapons and abilities in both gameplay modes.