George Fan created Plants vs. Zombies 10 years ago. To celebrate that anniversary, he's been showing off his original design documents and sketches on Twitter. As you can see from his notes, originally the enemies were supposed to be aliens rather than zombies—specifically the aliens from his previous game, Insaniquarium, which he was planning to make a sequel to. Once he drew his first zombie he changed his mind, and that original sketch bears a strong resemblance to the undead who eventually made it into the game.
