Night of the Dead 2 is the sequel to Night of the Dead, which began full-time development in early June. NOTD 2 is expected to be ready for Alpha testing in Febuary of 2014.
NOTD 2 features a main "root" storyline rather than multiple storylines to be chosen at the start of the game. Due to this, all classes will be available to be chosen as opposed to them being restricted to various storylines for lore and balance reasons. Additionally, the Chemical Expert will be replaced by the Squad Leader, and another class will be revealed at a later date. It is currently unknown what this new class will be, but several hints have been given on the forums by "Seekrit Agent Otis".
Rather than choosing between multiple storylines at the beginning of the game, NOTD 2 features a main "root" storyline where the storyline branches multiple times based upon the actions of the players during the course of the session. Gameplay types will include the main storyline, a "Black Ops" Mode, and Survival/Holdout. A competitive/deathmatch style mode is being considered, but is currently only speculation.
Rather than only primarily featuring Infested, NOTD 2 will feature multiple "races" of enemies: the Infested, Mechanicals, and Humans. The Infested of NOTD 2 have been outlined in a teaser post by Kithrixx, but details on the other two races are scarce. Additionally, enemies will feature "variance", which will add unit variety and challenge to later difficulties rather than just a net increase of health. Infested Variance involves the units mutating into tougher or more dangerous types, but it is unknown how it will influence the Mechanicals or Humans.