Call of Duty: Ghosts cheat codes:
How to Unlock Extinction Mode:
1.Start the Campaign under Regular difficulty or higher.
"Extinction Mode" will not unlock under Recruit.
2.Complete the first four (4) missions. Finish "Ghost Stories",
"Brave New World", "No Man's Land", and "Struck Down".
3.Finish the fourth mission and return to the main menu
to see the new selection; Extinction Mode.
Zelda and Doctor Who easter eggs:
During the "Federation Day" campaign mission,
after you enter the "CARANI" door, you can find a trophy
in the shape of The Doctor's TARDIS with the words "Award for Largest
Interior with Smallest Exterior", and next to it a Zelda rupee-shaped
trophy with the words "for most bushes cut and pots smashed".
There's also a trophy poking fun at the whole "world ending in 2012" event.