Man, I love me some Plants vs Zombies. Not sure how much I would have loved the game's original premise, Plants vs Aliens, though.

A post over on Ars Technica points out that, when it first began development, the hit tower defence game wasn't about the eternal struggle between plants and the living dead. It was a sequel to Insaniquarium, an older Popcap game about keeping fish safe from an alien invasion.

Once Popcap and the game's creator, George Fan started work, however, things began to change. Instead of being about fish, and aliens, the tower defence game soon began to be about plants and aliens and zombies. And the more they worked, the more zombies took centre stage, until the game made a clean break, stopped being a sequel to Insaniquarium, and became Plants vs Zombies.


Pictured here is some concept art from the game, showing some of the unused alien antagonists, plants that never made it into the game and the design document that took the game from traditional tower defence title into the side-scrolling affair it's famous for today.

Yesterday, David Roberts, CEO of Plants Vs. Zombies development studio Popcap shared with Kotaku the kind of all-too-logical question that surely explained the dramatic development shift from aliens to zombies: "How could [the aliens] get to Earth and not have the technology to kill plants?" Zombies, he implied, would be just stupid enough to be stopped by plants.

Aliens in the garden: the secret origin of Plants vs. Zombies [Opposable Thumbs]