It has recently been revealed, via members of the NeoGAF forum, that by pressing a combination of buttons within the Gears of War Judgment menu players could access the Warzone gameplay mode, a gameplay mode which has been available in all Gears of War games except Judgment.
Speculation lead to belive that Warzone would return as Paid-DLC, since a Season Pass is available which adds more maps and gameplay modes, however Peter Knepley, Senior Multiplayer Programmer at Epic Games, revealed that Warzone would not be included as DLC (which arrives on the 2nd April) but instead is part of the gameplay code that was left in the game and was needed to create the basis for the Team Deathmatch gameplay.
— Peter Knepley (@PeteNub) March 26, 2013
Either way in order to access this ‘Hidden’ gameplay mode players must go to ‘Versus’ and then Private Match and highlight Team Deathmatch. When Team Deathmatch is highlighted players must press A and B together and instead of the game loading up Team Deathmatch it will load up Warzone. The Gameplay layout (as demonstrated in our gameplay video) is the same as Team Deathmatch, except it has Warzone rules.
For the time being Warzone is ‘officially’ not meant to be part of the game, however by doing this method you can get a taste of what exactly it would be like to play the Warzone gameplay mode within Gears of War Judgment. The first DLC Pack, which includes execution mode, will be released on the 2nd April 2013.