I was standing in line at the local Thai restaurant the other day and a group of guys in front of me were absorbed in one of their iPhones. I asked one of them what they were playing and they said the new geoDefense Swarm adding it was a very cool game.
geoDefense Swarm is the latest tower defense game from Critical Thought. It only costs $.99 (introductory price) and reviewers call it the best of its kind. It gets high marks for its retro vector graphics and challenging game play. iLounge rates this game an A-.