Zombies stalked San Francisco streets on Thursday as social game maker Zynga ghoulishly introduced a game that lets iPhone or iPod Touch users slash and hack the undead.
Actors posing as the living dead were unleashed here and in Manhattan ahead of the "Zombie Swipeout" launch. The hordes enticed humans with free "blood pops" -- hibiscus and mint popsicles promising the "fleshiest" ingredients.
"We love zombies," said Zynga Mobile Germany studio director Matthias Hoechsmann, whose small startup gave the world the hit game "ZombieSmash" before being bought in October by the San Francisco-based social games star.
"What we love most is there are so many things you can do to zombies - anvils, machetes, baseball bats, landmines..." he continued as he gave AFP a preview of the new smartphone game.
"It's guilt-free killing because they are already dead."
"Zombie Swipeout" will launch globally in coming weeks.
The free, arcade style game has one rule: don't kill the good guy.
Cartoon zombies bounce into view on screen and points are scored by slaughtering them by slashing with fingers. Occasionally a human character arcs into the mix, and killing him ends the game.
"The object of the game is to slash, slice, bludgeon, explode, and freeze as many zombies as possible without harming Joey, the lone human survivor from ZombieSmash," according to Hoechsmann.
Hoechsmann's path to game design was an unusual one. He studied computer science and genome research in Germany, earning a doctorate degree.
Hoechsmann took a position at a California State university where he studied micro-organisms that could survive in extreme temperatures.
He was a college researcher and his brother was working on a doctorate degree of his own in Germany when the iPhone launched and "changed our lives."
"My brother and I grew up with games and played every game out there, so we learned something about programming and started making our own games."
"Zombie Swipeout" grows more challenging as players progress through levels. Extra points are award for moves such as head blows or chain kills.
Players can earn, or buy, weapons with special powers such as slowing enemies or adding time to games. Players are given 75 seconds to earn as many points as they can.
Leader boards rank friends weekly according to high scores and display special badges earned. And snapshots of "awesome kills" can be shared on social networking service Facebook or sent to friends by email.
Explore further: Body by smartphone