The first three things we should look at are the title, the original promo images and the first leaked shot. From these we can establish a rough time period, the protagonist, the outline of the plot and the location of the game. http://i.imgur.com/HLpLF.jpg Both of these pre event illustrations feature Big Boss, the protagonist of the cold war Metal Gear games (MGS3: Snake Eater, MGS: Portable Ops and MGS: Peace Walker) as opposed to his 'son' Solid Snake, one of the protagonists of the modern Metal Gear games. The dog in the picture is a Rhodesian Ridgeback, the same breed of dog was used in an early Fox Engine tech demo and appears on a new military patch illustration Kojima has released for a unit called the "Diamond Dogs". Angola is notorious for it;s blood diamond past and Miller mentions in Peace Walker that he's deploying members of his and Big Boss' PMC, Militaires Sans Frontiers, into Angola. The dog is a breed native to Rhodesia, so it's a dead set that the game or part of it is set in Africa. Big Boss starring would suggest it's set somewhere between 1975 -1985 (a lot of conflicts in Africa during this time) Next thing to look at is the first leaked image from before the gameplay footage. http://d1vr6n66ssr06c.cloudfront.net/wp-content/uploads/2012/08/mgs-ground-zero-1.jpg This image confirms it's Big Boss as the protagonist, alongside MSF's involvement (the badge on his shoulder) and the ol' stars n stripes confirms involvement of the American puppet Government lead by the Patriots. Which brings me on to the name. Ground Zeroes. Ground Zeroes as a phrase doesn't make sense, we all know what a ground zero entices, but multiples of it aren't written like that. If we switch the words around to Zeroes Ground it starts to make a lot more sense. Major Zero, the man behind the patriots and the subsequent hidden enemy of MGS lore post Portable Ops, and Big Boss split ways in the early 70s which lead to Zero having Big Boss cloned and subsequently trying to remove Big Boss from the world. Big Boss spends the later part of his life waging war on the Patriots and Zero. If we remove the e and replace it with an apostrophe we get "Zero's Ground". The tagline "from FOX, two phantoms were born" is a direct reference to Big Boss and Zero's old FOX unit and the subsequent events after the Boss' death in 1964. The Trailer - subbed http://www.youtube.com/watch?v=yhDZDgyrTLc We now know that the game, atleast this part, is set in Cuba. However players of MGS4 will remember darting around the globe in pursuit of Ocelot, so there's nothing suggesting this game won't progress into Africa. Especially given that it seems Big Boss is solely in Cuba to liberate Paz and Chico (characters from Peace Walker, Paz being an agent for the Patriots and Chico being a young child soldier with the Sandanista movement) The child in the cage is likely to be Chico. The military guys there seem to be from MGS3/Portable Ops' FOX unit, another massive indication to Zero's involvement. The burned man is a mystery still, he's definitely not Volgin from MGS3 despite physical similarities, his outfit is very reminiscent of Vardinov from Peace Walker, so it could be him.
