Every time i play this game i infect the harder places after constant restarting but there is always an easy country to infect i haven't infected. frustrating game but i love it :)
my bad about last comment i accedently clicked the button lol. but as i was saying if anybody is struggling with the spartan mini game, i found it easiest to buy the Quaker fully upgrade all of it, then buy as many repairman as you can and then upgrade the barricade as much as you can.. sorted worked for me and i hope this helps as my previous advice
i done a little test on the zombie mini game to help all of the people who aren't so good at this game. When i used the pistol i lasted 2:02 and when i used the shotgun i lasted 2:37... if you do use the shotgun just remember to not wait for the gun to fully reload and dont shoot after its only reloaded one bullet. Hop this helps =]