User blog comment:Crazy sam10/Official Extinction teaser released/@comment-5610200-20131027180021/@comment-3967954-20131027180255

Aliens in the campaign would actually put a lot of people off the game. If you recall when the first Black Ops II trailer was released, people were saying it was ripping off Halo purely because it was set in the future. I'm not particularly hyped for Ghost's campaign, but most people play CoD's campaign for action-adventure military-themed stuff, not aliens. I feel that implementing aliens into a survival mode is probably the best choice.