The "Silver Shield" in the context of Mortal Kombat vs. DC Universe for Xbox 360 likely refers to a specific edition or version of the game, such as a "Combo Pack" or a retail-specific product, rather than a unique gameplay feature. This 2008 crossover fighting game pits Mortal Kombat fighters against DC Universe heroes, featuring a new fighting system with mechanics like Freefall Kombat and Klose Kombat, a unique storyline, and iconic arenas from both universes. The "Silver Shield" marking is a common indicator for various versions of Microsoft-published Xbox 360 games, often appearing on the DVD case packaging.