The "Dimension Shellshock" DLC for Teenage Mutant Ninja Turtles: Shredder's Revenge recently arrived on console and PC, adding new playable characters, an addictive co-op survival mode, and more. To learn more about the decision-making and co-op balance behind both the main game and "Dimension Shellshock," we spoke with Frederic Gemus, Game Designer at Tribute Games.