My game crashed. I was fighting a dragon and right in the middle it just crashed. Other then that and a few other little issues this is a pretty good game.
I think having missions after wave 30 would be nice. Having the backpack upgrades doubled is really nice but it can still take a while to get enough money for upgrades.
more squads and some different functions like patrol so they'll move around the map and look of zombies or one to make them automatically go to a new outbreak. or later on have one to make them go get the nearest scientist or pilot
 "Feudalism III"){kind=icon}
 "The Peacekeeper"){kind=icon}
 "The King's League: Odyssey"){kind=icon}
 "Class 3 Outbreak"){kind=icon}
 "Epic War Saga"){kind=icon}