The Great Giana Sisters/WMG

Giana's super form in the DS version is an expy of Maria.
Only here because Word of God currently refers to Giana's super form as Punk Giana. But if you think about it, didn't Maria always have red hair? They couldn't call it Giana Sisters unless they had both sisters in there SOMEHOW. So how do you solve the DS version being a one-player game and thus not allowing for a player two? Make Player one and player two one in the same!

Giana's super form IS Maria.
Maria died between Great Giana Sisters and Giana Sisters DS. Those power up balls? They allow Giana to channel the spirit of her deceased sister.