Call of Duty 4: Modern Warfare is a 2007 first-person shooter video game developed by Infinity Ward and published by Activision for Microsoft Windows, OS X, PlayStation 3, Xbox 360, and Wii. A handheld game was made for the Nintendo DS. The game was released in North America, Australia, and Europe in November 2007 for video game consoles and Microsoft Windows.
As opposed to earlier games in the Call of Duty series, the game features modern equipment and new features, many exclusive to the multiplayer part of the game, such as "killstreaks"; killing a number of enemies without the player dying in between kills allows access to various assets including airstrikes and helicopter support. A character can be positioned in one of three stances: standing, crouching, or prone, each affecting the character's rate of movement, accuracy, and stealth. Using cover helps the player avoid enemy fire or recover health after taking significant damage. As such, there are no armor or health power ups. When the character has taken damage, the edges of the screen glow red and the character's heartbeat increases. If the character stays out of fire, the character can recover. When the character is within the blast radius of a live grenade, a marker indicates the direction of the grenade, helping the player to either flee or toss it back to the enemy.