Ngmoco has announced the release of Star Defense for the iPhone and iPod touch, a new strategy game that offers a fresh twist on the “tower defense” genre. IT costs $6.
You can battle friends in asynchronous multiplayer action over Twitter, Facebook or e-mail; defend seen different worlds each with distinct path layouts, enemy types and immunities and weapon choices; engage different levels of difficulty - easy, normal and hard; collect medal commendations; and more.
Star Defense is compatible with iPhone OS 2.2.1 or later.