Like in some of the previous Call of Duty games, there's no health bar. Instead, the edges of the screen become red and blurry, and the sound of the character's heartbeat gets louder when injured. However, hiding behind cover will recover all injuries. Although the game has a realistic look and feel, including the ability to shoot through flimsy materials like wood, there are a couple of sequences where it feels a little too arcade-like, especially during a high-speed car chase where the player can't shoot the driver of the pursuing car or blow out his tires. Furthermore, Modern Warfare uses an autosave system, but doesn't offer an option to reload the last saved checkpoint. If things suddenly go bad, the only way to get back to the last save point is to either get killed and automatically reload, or quit to menu and return.

Multiplayer offers a rich list of options and also works much like a role-playing game. Players rise in rank by wracking up kills and achieving objectives to earn experience points. Ranks unlock more classes that feature different weapon loadouts and traits called "perks." Eventually, players unlock the ability to build a custom class and can equip themselves with guns, attachments, grenades and up to three perks, including radar invisibility. Additionally, dying has its benefits in multiplayer. Death is followed by a kill-cam that recounts the player's final seconds, seen through the eyes of the killer. This gives players a chance to analyze playing style and figure out a way to exact some revenge.

Call of Duty 4: Modern Warfare has just about everything anyone could want from a shooter. There's an intense single player campaign with great characters and an interesting storyline, and it follows-up with great multiplayer action. If yo