Aliens in the garden: the secret origin of Plants vs. Zombies

It goes without saying that we love Plants vs. Zombies here at Ars Technica, especially the pocket-sized iPhone version of the game that was just released. If you haven't played it, you can download the free demo here and even get 10 percent off if you decide to buy the full game. It's a bizarre, funny, and addictive strategy title with a quirky art style, but the most surprising thing about it is that it was originally supposed to be an entirely different game.

What many gamers don't realize is that Plants vs. Zombies started out as a sequel to Insaniquarium, a strategy game that involves growing an aquarium's population while simultaneously protecting the fishes from an alien invasion. PopCap recently shared some original concept sketches for with us, and the evolution from sequel to fully original title is fascinating.