Planning
It is a really fun game. After 5000 zombies killed I have realized there is a finite amount of toxium doh! So while lvl 3 is achievable (400 pts) if you try hard enough your end is always near and unlocking the last 2 zombies takes *a lot* of work. Graphics also good.
Wazzybaby about
BioDefense: Zombie Outbreak, v2.0