Free BioDefense: Zombie Outbreak or BioDefense HD (iOS)

- Unique Mix of RTS and TD
- Play endless Survival Mode to unlock more content
- 10 Missions provides fast challenges
- 6 Unique Enemy Types with different behavior
- Large waves of attacking enemies
- Research Tech and upgrade your buildings
- Unlock Missions and Enemy info
- 25 OpenFeint Achievements
- Compete on OpenFeint Leaderboards