The Herd Mode DLC is a DLC available to anyone who pre-ordered The Walking Dead: Survival Instinct at GameStop. The DLC adds a new survival game mode where the player must fight limitless waves of hordes of walkers. The DLC was released to the public on April 16th, 2013 for purchase on Xbox Live Marketplace for 240 Microsoft Points and Steam for $4.99/£3.99.