The press embargo for Halo 4 was lifted last week, at the media event at 343 Industries' headquarters in Seattle, Washington. The developer revealed the first and third missions from the game's campaign, along with the new "Infection" game mode. According to leaked screenshots from the French Official Xbox Magazine, the zombie-killing Infection mode allows players to be the being-consuming Flood.

The Flood are confirmed not to return in Halo 4, having appeared in the three mainline Halo games. Infection was a fan-made gametype introduced in Halo 2; Halo developer Bungie introduced the mode in Halo 3, though the large scale maps were removed. It was later introduced in Halo: Reach, again with smaller teams. Dubbed "Zombies," the players move faster but are weak. 

According to Halo Destiny, OXM France attended the media event and reported that the "Infection" more casts opposing players as human-infected Flood. The players have claws and enhanced vision, though it is not clear whether movement speed or damage is altered. In Halo campaigns, the Flood can jump large distances, run fast, and use weapons.

Ten players can play in the Infected mode, and two start the game as Alpha Zombies. The aim is for survivors to avoid death by Flood and survive until the time runs out. It remains unconfirmed whether weapons will be less or more effective against Flood: in previous Halo games' campaigns, powerful weapons like the Shotgun and Rocket Launcher are called upon fo face the Flood, and weaker weapons like the Assault Rifle and Battle Rifle are not as effective.

Halo 4 will be released on November 6 on Xbox 360.