i just got a new 72 pin for my old nes, so i'm going through all my games (only about 35 or so) and opening them up and cleaning them.
i'm about half way through and i get to Metroid. It clearly has a spot for a battery, very similar to my Zelda (the only battery one i've opened so far)
I'm aware that Metroid and Kid Icarus where the first password games, i'm wondering if they were originally intended to be battery games??? Or where battery games developed after password games?
Just a thought, i figure someone here might know.