Ridiculously high difficulty spike

[Whitewave]

Bought this last night and was having a blast infecting the world, when all of a sudden the humans are ten times stronger than a whole horde of zombies. I thought maybe I was doing something wrong, so I reluctantly used cheat engine to give myself all the rewards, and even with EVERYTHING unlocked it's still impossible. Sorry, but that's just not fun. The only reason I'm not requesting a refund is because the game has just been released and I'm hoping the dev can put out a fix for this otherwise excellent game.