1. Mined Games (Black Ops II)
https://www.youtube.com/watch?v=F_1L_HADyPY This one is the sort of thing that proves gamers are geniuses, as the process to unlocking both the Mined Games achievement and subsequent hidden dialogue/exchange on the Buried map is so convoluted, complex and obscure it'd take a true mastermind to figure out on their own. As such, I've included Youtuber LiamFTWinter's rundown of how to trigger the easter egg, as the amount of steps required to pull it off would require an article in itself. Needless to say, when all's said and done you'll have unlocked an extra weapon slot for your character, additional (and conclusive) story dialogue for the zombie mode, a few bonus weapons that can only be obtained this way and access to a permanent Fire Sale, showing where the mystery boxes in the level are. Whether you'll do it yourself or just watch the clip and give up though? That's over to you. Are there any we've missed? Let us know in the comments what your favourite easter eggs and hidden references are!