With the original developers returning to the helm of the long-running Call of Duty franchise, chapter 4 has the player assume the role of a British SAS squad member in various missions across Europe and a US Marine in the Middle East, fighting against fictive global terrorism driving persona.
Without deviating from its roots, Call of Duty 4 is an actual military-based FPS, with the player fighting in a fictive scenario and a current-day world, against modern opponents and weapons. Several campaign-based tasks let the user play as two separate troops from two different military enforcement specialties. Multiplayer is accessible as usual, with many game styles.
The objectives in the single-player campaign give the player several tasks to complete and lead them through many twists and turns as the plot unfolds. A vast arsenal of weapons is available, with various alternatives to fit different playing styles. For the first time, the game runs on a proprietary 3D engine based on id Tech standards, with physics, dynamic lighting, bloom, and depth-of-field.
