"Nothing to do" this is a little more tricky than you think.  You have to complete all the in-game achievements in order to complete this quest.
You must do the following in this order:
1.) Upgrade everything
2.) Make sure you do all the Armor Games quests during one play through.
3.) Destroy every town
4.) After completing steps 1 through 3 click New Game + (this is when I obtained the quest. I had to enter a New Game +

Why do you have to:
2.) Make sure you do all the Armor Games quests during one play through.

Because, Infectonator 2 as a set of in-game achievements that are the Armor Game quests. When you restart a new game, you will keep all of your Armor Games quests, but you will lose your in-game achievements. So you have to do the two sticky goo on lvl 1, unlock the middle east, summon Freddy, etc. All in one play through.

HUMONGOUS PROBLEM

i have unlocked the middle east and destroyed all the towns in it and haven't got the achievement!! What should i do i can't replay any towns in the middle east!!!

please help

@Reton8
You can actually check all AG QUESTS, by simply clicking on "STATS" .
By playing this game for alredy 3 times I am pretty sure I did it all right.

You can actually check all AG QUESTS, by simply clicking on "STATS" .

Yeah you can check if they're done. I was just saying, just because You have the armorgames quest, doesn't mean you have it in game (if you have started over).

So you are certain all the achievements said complete? In that case I can't help :\\ That stinks to have to beat it three times.

Piece of Cake

Nice, very nice, was and still is one of my fav games... sadly i have only 11 from 13 quests yet, so 2 to go^^

@Reton8
Well completed it once again :D and this time I got that quest :)

Thanks for tips,  u were right,  guess I have missed something before :)

"Make sure you do all the Armor Games quests during one play through."

I didn't realize that once I destroyed every town, the game would end and I would not be able to finish upgrading things. Now I have to start a new game and do everything over again.

Attacking National park without destroying it over and over again it's by far the best way of farming tons of gold :)