I saw a great HotS campaign idea from Cloverfield on battle.net, so i thought I'd give this a go.
Pokemon Idea
A game from the anime Fooley Cooley (FLCL). You are a servant of Canti, and you most burn down the sity of Endsville
Just run around, kill stuff, level up, use abilities, get items.
Control a test subject that goes around and evolves as he kills stuff