iOS Essential but Needs Co-Op

Ive had 3 iOS devices and this has ALWAYS been a first purchase for me. Its worth no more than $1 but its worth every penny. It is pretty repetitive but its an amazing game. Only wish is to have co-op survival. Gameplay is perfected; but features could get an update. There for 4/5.

99Carnies about BioDefense: Zombie Outbreak, v3.1